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Class J^ . ^ 
Book «Ca B3_ 



Gop}TightN".. 



COP^'RlGliT DEPOSIT 



Introduction 



TO THE 



SOILS of CALIFORNIA 



BY 



GILBERT ELLIS BAILEY 

Head of the Department of Geology, University of 

Southern California, Los Angeles, 

California 




Los Angeles, Cal. 

WESTERN EMPIRE PUBLISHING CO.. 

1913 



Copyright 1913 

by 

Gilbert Ellis Bailey 

All rights reserved 



>^xrv^ 






■WOODS." Inc , Printers and Eneraver* 
Lot Angele*. Cal. 



OCU357485 



FOREWORD 

A preface should not be an apology for spreading printers' 
ink on paper. It should be a statement of the author's pur- 
pose ; something to give the work more force, and enable it 
to do the good it was planned to do; something to place the 
reader in closer touch mentally with the writer. 

The soil is the principal asset of the nation. It provides 
the raw material for upward of sixty per cent of the gross 
value of all the products of manufacture, and the railroads 
and steamers with a large part of their tonnage. It supplies 
the population of the country with most of their food and 
clothing, with much of the material for their houses and house 
furnishing, and with part of their fuel. In spite of these facts 
this "the greatest of assets" is neglected, abused and mis- 
understood. This slight superficial and inconstant covering 
of the earth should receive a measure of care which is rarely 
devoted to it. Every owner of land needs to know something 
of the part of the earth he is dealing with or in. The soil is 
a precious inheritance that should be jealously guarded and 
protected instead of being abused and neglected. It is abused 
mainly through ignorance rather than intention, and one object of 
the author is to help a little in removing some of this ignor- 
ance. The soil must be understood. One needs at least some 
definite knowledge of its physical and chemical character, its 
hygiene, productive capacity, and adaptability to crops. 

Too many look upon the soil as something essentially 
unclean, in which seeds manage in some mysterious way to 
grow. This attitude should be changed to admiration of the 
beauty, harmony, and order of the mechanism of the soils, 
on which the existence of all living beings depend ; to the 
vast array of forces involved ; to the perfect order of their 
action ; and to the design, purpose and intention shown in 
their construction. Long familiarity has placed over the soil 
the veil of the commonplace and hidden the dignified meaning 
that exists in its structure. Men look at the soil without 
seeing, and walk over it without thinking. They forget that 
the solid and substantial wealth of our nation comes from the 



4 Soils of California 

country and not from the city, and that this hard-earned 
wealth should be used largely to improve the country and its 
institutions. We must never in any of our philosophies get 
away from the land. One object of the author is to show 
that the commercial value and relation to crops can be seen 
in the field from the physical character of the soil. 

The grouping by classes, such as the loams, sandy loams, 
silt loams, etc., brings out best the uses to which the soils 
are adapted, and calls attention to the similarity of soils and 
to the possibilities of the extension of industries into new 
localities, climate and economic conditions permitting. The 
time has passed for trying to plant round pegs in square 
holes; for using a thousand acres of citrus land for raising 
two hundred pigs; for using lima bean and sugar beet land 
for Texas steers; or for raising chickens and Belgian hares 
on choice date land. The cry of common sense is "intensive 
farming," "a little land well tilled, and an ample purse well 
filled." .';^pm 

The new agriculture is advancing on the Pacific Coast 
with strides that attract the attention of the world, and one 
object of this work is to make accessible information that is 
scattered through a great number of government and indi- 
vidual reports that are not accessible to most people, and to 
arouse an interest that will lead the tillers of the soil to study 
and investigate for themselves, and to point out the way. 

The soil and its problems offer a field of study of the 
highest importance not only to the development of the welfare 
of the human race, but to obtaining personal financial returns. 
This introduction to our soils is an attempt to place in read- 
able form some of the results of scientific thought and dis- 
covery, and to prove that a minute study of the soil is worth 
while. The educational value of any book or subject lies not 
so much in the actual information presented as in its arrange- 
ment into systematic treatment so as to develop a philosophy 
of the subject. Schools will not make farmers or house- 
keepers but they can stimulate an interest in youth in the 
problems connected with these two important vocations and 
develop clear thinking, sound argument, constructive imag- 
ination and effective application. 

The attempt has been made to be practical rather than 



FOBEWOBD 6 

scholarly, direct and simple instead of technical, and of service 
to every man who owns an acre or is getting a living from 
the soil rather than for the class room or library. An effort 
has been made to avoid unnecessary technical words and terms 
so far as this can be done without dodging or shying at 
unfamiliar words necessary to embody new ideas. The inde- 
pendent farmer wants to know the whys and wherefores, and 
he wants a simple statement of observed fact and the most 
positive proof of the correctness of such statement; therefore, 
only the facts have been compiled, and the reader referred 
to special works for the theories. 

Nothing original is claimed, but all sources of data have 
been freely used and obligation to a large number of author- 
ities is hereby given and acknowledged. I desire especially to 
acknowledge the assistance given by Mr. E. E. Free, of the 
U. S. Bureau of Soils; Mr. M. V. Hartranft, of the Western 
Empire and Fruit World ; and Hon. Wm. E. Smythe, whose 
life has been given to making each individual do his duty to an 
acre, and each acre do its duty to the individual and to the world. 

As to mistakes, if you point them out they will be cor- 
rected next time; but the farmer or writer who hesitates for 
fear of mistakes will never accomplish anything. As to 
critics, — remember the words of the scientist: "Animated 
beings who inhabit vitrified tenements ought not to project 
lapidary fragments." 

Los Angeles, 1913. 




University of Southern California 
los angeles 



PART I 

CHAPTER I 

AGRICULTURAL GEOLOGY 

THE SOIL is the one indestructible, immutable asset that 
our nation possesses. It is the one resource that cannot be 
exhausted, that cannot be used up, but if properly cared for, not 
only clothes and feeds us but improves with age and proper 
treatment for the continued use of posterity. 

It forms the basis of our industrial wealth and a large por- 
tion of our foreign exports, yet we are taking up the last of our 
public lands while the country is so sparsely settled that less 
than one-fourth of the land nominally in farms is actually under 
cultivation. From these lands we obtain from only one-third to 
one-half the yield per acre obtained on the older soils of Europe. 

It is dependent upon us to study the soil, to understand its 
origin, composition, properties, functions, and relations to crops, 
to understand the changes brought about by cultivation and crop- 
ping, to win from the soil not only for our present needs, but to 
increase the yields for the larger population that follows. 

The problems are many and some are complex. The weight 
of an acre of soil one foot deep is about 2000 tons. The art of 
soil management is to so manipulate and handle this 4,000,000 
pounds of raw material at a cost of ten or twelve dollars an 
acre as to produce the greatest quantity of profits, and still leave 
the soil unimpaired for future generations. 

The more a man knows of the nature of the soil the better 
prepared he is to handle it properly. 

AGRICULTURAL GEOLOGY. Since all soil materials 
form a part of the structure of the earth, their origin, character, 
and classification constitute a part of the field of geology. Agri- 
cultural geology is a history of the outer mantle of the earth, its 
materials, origin, character, uses and value. 

The soils of California come from a great variety of geologic 
formations. Almost the entire geologic column from the Cam- 
brian to the latest Quaternary is represented. The rocks of each 



8 Soils of California 

of these formations has weathered into soil somewhere in the 
state, giving the student exceptional opportunities for study. 
Over 200 soil types have so far been recognized by the United 
States Department of Agriculture and mapped in California. The 
crops produced range from the wheat, corn and barley of 
the colder climates to the rice and cotton of the South ; from 
apples, peaches, and pears to oranges and lemons ; from hops to 
wine and raisin grapes ; from pine forests to date palms ; from 
blackberries to alligator pears. The soils themselves range from 
those at the feet of living glaciers to those in the midst of deserts ; 
from meadows 12,000 feet above sea level to burning sands below 
sea level. No other state in the Union presents such a variety 
of soils or of products, or offers such an opportunity for invest- 
tigation. 

THE EARTH is one of the organisms of the Universe in 
which all parts work together harmoniously according to plan, 
intention, and design, as much as those of an animal or plant. It 
was born, will reach maturity, pass through old age, and finally 
die (that is, change form) only to renew its existence in another 
form. The earth is not therefore in any of its parts to be con- 
sidered as a dead, inanimate thing, but like a tree it is most active 
on the outside. The mantle of the earth, or soil, is not a change- 
less, lifeless, inanimate thing, but is ever moving and changing, 
and teems with life and activity . 

The relation of the earth to the sun determines the amount 
of heat the soil receives, and gives us the seasons. The forms of 
the earth's surface determine the angle at which the parallel rays 
of the sun strike the different portions of the mountains, hillsides 
and plains, and the amount of heat per square mile, giving tem- 
peratures that range from frigid to torrid. The inclination of the 
earth axis combined with its daily and yearly motions determines 
the seasons at the various latitudes. The annual revolution 
around the sun gives a succession of seasons, warm, cold, wet or 
dry, establishing the principle of rotation, or alternating periods 
of rest and activity for the soils. The daily rotation of the earth 
on its axis gives alternations of light and darkness, heat and cold ; 
giving soils, plants and animals short and frequent periods of 
activity and rest. The structure of the earth, like the structure 
of a plant or animal, includes solids, liquids and gases. 

THE SUN, as large as 300,000 earths, furnishes by wireless 



Ageiciiltueal Geology 9 

the light, heat, chemical and electrical rays which keep things 
moving and active upon the surface of the earth. It is clearly 
these forces from the sun that cause all the movements of animal 
and vegetable life, and all the growths of roots and stems, the 
germination of seed, the opening of the bud, and the ripening of 
the fruit. 

THE ATMOSPHERE is an intimate mixture of all sub- 
stances that cannot take a liquid or solid state at the temperatures 
and pressures that prevail at the earth's surface. It contains 
79 parts of nitrogen, 21 parts of oxygen, .03 parts of carbonic 
dioxide, and small quantities of argon and other rare elements. 
The water vapor contents vary from time to time and from place 
to place, as do the gases that come from volcanoes, cities and 
manufactories, and a great variety of volatile organic substances. 
Dust and other forms of solid matter are often suspended in the 
atmosphere as impurities. It is mobile and active and has great 
direct and indirect effect upon water, rocks and soils. It is a 
thermal blanket distributing and equalizing temperatures, and 
sustaining and promoting life. 

THE HYDROSPHERE. The water which lies upon the 
surface of the earth would form a universal ocean a little less 
than two miles deep if the earth was a perfectly smooth sphere. 
It occupies 72 per cent of the earth's surface and is apparently the 
greatest of all geologic agents, constantly changing the forms of 
land surfaces and the temperature. It is destructive and con- 
structive, ever tearing down and building up. The historical 
records of geology are largely due to the fact that the waters 
have buried in systematic order relics of the life of successive 
ages past. 

THE LITHOSPHERE. The ground upon which we stand 
is a part of the outer crust of the lithosphere or rock sphere of 
the earth. It is composed of loose, incoherent material commonly 
called earth or soil, and consists of clay, sand, gravel, pebbles, 
and boulders, or mixtures of these. The great lithosphere or 
rock globe is an oblate spheroid with a polar diameter of 7,899 
miles and an equatorial diameter 26.8 miles more. Its surface 
area is 196,040,700 square miles, of which only 55,153,500 square 
miles are land, and only a small portion of this is soil capable of 
cultivation and supporting human life. 

The atmosphere and hydrosphere are mantles rather than 



10 Soils of Califobnia 

true spheres, and both penetrate the lithosphere to some extent. 
In order to understand the origin of soils, their properties and 
value, one must know the character of the lithosphere and the 
action of the atmosphere and hydrosphere upon it. 

THE FACTORS. The character of the soil of any region 
depends upon two great groups of factors: (1) The character 
of the material from which is has been derived; (2) the processes 
by means of which this material has been converted into a soil 
capable of supporting plant growth. 

The first has to do with soil-forming materials which are 
part of the lithosphere, and the second with soil-forming processes 
which are largely the action and reaction of the atmosphere and 
hydrosphere upon the lithosphere. 

The two factors are intimately associated, and any given soil 
is always the resultant of a definite combination of these soil- 
forming factors. Uniformity in the factors gives uniformity in 
the soils, giving definite soil types ; while any variation in the 
factors gives a change in character amounting to a phase or sub- 
type of soil. A knowledge of these factors is therefore essential 
to a proper understanding of the soils of any region. 



CHAPTER II 
SOIL FORMING MATERIALS 

ROCKS. The rocks at the surface of the earth are all frag- 
ments of still older rocks of former geologic periods, broken up 
and more or less decomposed, and form a sheet of loose frag- 
mentary material that is called mantle rock because it overlies 
and covers the compact, coherent mass below that cannot be easily 
broken up or removed and is known as bedrock. 

Where the bedrock projects through the soil, as on a hillside 
or along the banks of a creek, it is called an outcrop. If the 
bedrock lies in distinct sheets or layers, called strata, it is said 
to be stratified. 

The common kinds of stratified rocks like shale, sandstone, 
and limestone, are also called aqueous or sedimentary rocks 
because they were formed in water on ocean bottoms, or lakes, as 
sediments that in time became hardened (indurated) into rock. 
A rock may contain material of one kind only, as limestone, or it 
may contain material of several kinds as in the case of granite. 
It may be loose or unconsolidated like sand, or it may be solid 
(consolidated) like sandstone. 

It is desirable to know not only the kind of rocks from which 
the soil is formed but also in what physical form these compounds 
exist. Examine a rock with a magnifying glass, or place thin 
sections under a microscope, and it is seen that all rocks are com- 
posed of particles of different sizes and shapes and kind, which 
are sometimes held together weakly .and sometimes firmly. These 
particles are called minerals; for example, we say that the rock 
granite is composed of the minerals mica, quartz, and feldspar. 

Rocks are classified according to their chief mineral con- 
stituent. Rocks composed largely of lime are said to be calca- 
reous; of quartz, siliceous; of iron, ferruginous; and of clay, 
argillaceous. If eruptive rocks contain over 60 per cent of silica 
(quartz), they are said to be acidic; if less than 50 per cent of 
silica, they are spoken of as basic. Rocks are often named 
according to their structure as crystalline, such as granite and 
marble ; vitreous or glassy, as obsidian and other volcanic rocks ; 



12 Soils of California 

coUodial or amorphous in structure, as siliceous sinters and flint 
nodules ; or as fragmcntal when composed wholly of the frag- 
ments of pre-existing rocks held together by clays or cementing 
material. Where rocks Have been forced up through fissures 
penetrating other rocks, they are said to be intrusive. Rocks 
formed by heat, as the lavas, are called igneous. If igneous or 
sedimentary rocks have been radically altered in appearance or 
character, especially one that has been rendered crystalline by 
heat or pressure, it is called metamorphic. 

Adobe is classified as a rock when considering the thick 
clayey accumulations in the basins and plains of the arid region. 
It is a fine clayey or silty deposit formed by the gentle wash from 
slopes that lodges on the flats below. Clay, considered as a rock, 
is a term commonly applied to any soft, unctuous, adhesive de- 
posits composed largely of aluminum silicates. Many so-called 
clays are chiefly siliceous silts or loams and not true clays. Note 
the definition of clay in soil anaylsis. Conglomerate, often called 
puddingstone, is a rock composed of rounded pebbles, or of 
unconsolidated gravel. Drift, in common American usage, is a 
mixture of clay, sand, gravel and boulders formed by the action 
of glacial agencies. Eolian rocks are deposits formed by wind, 
embracing especially sand dunes and much of the loess. Gneiss, 
a foliated granite and often called stratified granite, consists 
normally of quartz, mica, and feldspar. Granite is a granular 
crystalline aggregate of quartz, mica, and feldspar. It is pop- 
ularly, and properly, used for any distinctly granular and crys- 
talline rock. Granite and gneiss crumble first into barren gravel, 
then the quartz crumbles into sand, and the mica and feldspars 
decay into clays. Greenstone is a comprehensive term used to 
designate igneous and metamorphic crystalline rocks of greenish 
hue and of intricate and minute crystallization. It is a convenient 
field term where the mineral constituents cannot be readily deter- 
mined. They are usually, in California, dolerites, diabases, or 
diorites. Igneous, or fire-formed rocks, diflfer widely in composi- 
tion and texture, and therefore weather into a great variety of 
soils, some of which are poor, and some of which are exception- 
ally fertile. Lava is a molten rock of variable composition com- 
ing from vents or fissures and solidifying at the surface. They 
vary in fertility according to their composition. Limestone is a 
rock composed primarily of calcium carbonate, but is called 
dolomite if it also contain considerable carbonate of magnesia. 



Soil Fobminq Matebial 13 

Marble is pure crystallized limestone, or metamorphozed lime- 
stone. Loess is a very fine porous siliceous silt containing some 
calcium material which often collects in nodules. It is charac- 
terized by its standing in vertical walls and weathering so slowly 
that letters cut into it remain distinct for years. Its origin is still 
a matter of controversy among geologists, being held by some as 
purely eolian, by others as fluvial (stream) or lacustrine (lake) 
formation, and by many more as partially eolian and partially 
aqueous. Mantle rock or regolith is the earthy mantle that covers 
the indurated rocks, and consists chiefly of residuary earths, soil, 
and subsoil. Marl is an earth formed largely of calcium carbon- 
ate, usually derived from the disintegration of shells, or from 
the calcareous secretions of plants. The term is also applied to 
glauconitic and other fertilizing earths. Ooze is a soft deposit 
of the deep seas, and is characterized mainly by shells of micro- 
scopic size. Sandstone, or indurated sand, consists of grains of 
quartz, or grains of the various hard silicates. Quartsite is meta- 
morphosed or crystalline sandstone generally. Shale is a more 
or less laminated rock consisting of indurated muds, silts, or clays. 
They are often the hardened soils of former geologic times that 
weather into silts and clays and make good soils if not too com- 
pact. Slate is a clay rock finely laminated and fissile, and can be 
split into thin sheets like common roofing slate. It is apt to 
weather into clay soils that are heavy and compact. Till is a 
stony or bouldery clay, or rock rubbish formed by glacial action. 
Tuff, or tufa, embraces the ashes, cinders, etc., of volcanic erup- 
tions. Calcareous tufas embrace also the granular and cellular 
deposits of springs, such as those of the Mono Lake district. 

MINERALS. Of all the hundreds of minerals named and 
classified, less than fifty are important geologically or commer- 
cially, and only about a dozen of them are used in forming the 
common rocks from which the soils are derived. Quartz is 
familiar to all as the chief constituent of sand. It is composed 
of 46.7 per cent of silicon and 53.5 of oxygen. It occurs in most 
rocks as grains without definite shape. It will scratch glass and 
cannot be scratched by a knife. When rocks decompose, the 
minerals are broken up and the elements enter into new combina- 
tions, but the quartz remains unaltered and is washed away or 
blown away, forming sand, sandstones, siliceous rocks, quartzites 
and cherts. It is an ingredient of all soils, giving them lightness, 



14 Soils of California 

drainage, and promoting aeration. Feldspars — There are sev- 
eral kinds of feldspars, composed of silica and aluminum, together 
with potassium, calcium, and sodium. In the orthoclase or potash 
feldspars, potassium is the distinguishing element, from 6 to 16 
per cent being present. Feldspar is not quite so hard as quartz, 
and is not readily scratched by the knife. The faces of the 
crystals are fiat and glistening, distinguishing it from the quartz. 
The color is variable, from flesh-colored to white, yellow, pink, or 
red. Clays result from their rather ready decomposition. Am- 
phibole is a type of iron-magnesium-silicate minerals, the most 
common being hornblende, which is composed of aluminum, mag- 
nesium, iron and calcium, which enter the soil on the weathering 
of the mineral. Mica is a complex silicate that is easily identified 
as it is the only common mineral that splits into very thin paper 
like elastic leaves. The light colored potassium mica called mus- 
covite is used under the name of isinglass or mica in stove doors 
and lanterns. A dark colored mica containing iron, magnesium 
and other elements is called biotite ; that containing lithia is called 
Icpidolite, and that containing sodium, paragonitc. Lepidolite is 
found in San Diego county as the violet colored gangue rock in 
which the gem tourmalines are found. Mica is readily seen in 
many soils as glistening scales, especially in soils derived from 
granitic rocks, and such soils are said to be micaceous. Calcite is 
calcium carbonate containing 56 per cent of lime and 44 per cent 
of carbon dioxide. It is the principal constituent of limestone 
and is easily scratched with a knife and effervesces with an acid, 
distinguishing it from feldspar. Lime is not only a necessary 
plant food but also influences in a marked degree the physical 
condition of the soil, and the process of nitrification. It makes 
stifif clay soil more porous, more easily pulverized, and therefore 
more productive. It corrects the sourness or acidity of soils and 
forms an essential ingredient of all plants. Gypsum is the hy- 
drous sulphate of calcium, 32.5 per cent of lime, 46.6 of sulphur 
trioxide, and 20.9 per cent of water. It is a white mineral, much 
softer than calcite, being readily cut with a knife. It does not 
effervesce with acids as calcite does. When calcined and ground 
it is the common plaster-of-paris of everyday use. It reacts 
with carbonate of soda (black alkali), forming sulphate of soda 
and carbonate of lime and is used therefore as a corrective on 
certain alkali soils. When not calcined but simply ground it is 
known as land plaster and used as a fertilizer. Kaolin is the 



Soil Forming Material 15 

hydrous silicate of aluminum, containing 46.5 per cent of silica, 
39.5 of alumina, and 14 per cent of water. It forms the basis 
of clay and is very soft and earthy. It is derived largely from 
the decomposition of feldspar and is colored generally by iron or 
other impurities. Pure white kaolin, or kaolinite, is known as 
china clay and is the basis of pottery work. Hematite is iron 
oxide, containing 70 per cent of iron and 30 per cent of oxygen. 
It is one of the leading iron ores, occurring in both the hard and 
soft forms. It gives a red streak when rubbed on a surface harder 
than the mineral. Iron from hematite is found everywhere, 
coloring soils and rocks red, yellow and sometimes green. Apatite 
is essentially calcium phosphate with some chlorine or fluorine 
and about 40 per cent of phosphoric acid so necessary to all plant 
growth. It is not common in massive form but is fairly common 
as a mineral in certain rocks. Pyroxene is a type of a large group 
of rocks, forming iron-magnesium minerals, and is usually a 
magnesium-iron-calcium silicate. It is not readily identified except 
by those familiar with mineralogy and its identification in soils 
is of minor importance. Chlorite is a type of a somewhat import- 
ant group of secondary minerals identified by their green color, 
softness, smooth or unctuous feeling. They are usually alumi- 
num-magnesium-iron silicates with water which they give up to 
the soil under decomposition . 

ELEMENTS. The minerals that form the rocks are in turn 
composed of chemical elements. Of all the elements known to 
the chemists only the following are important in the soils. They 
are given in the order of their importance in making up the 
lithosphere : 

Per cent in 
the lithosphere 

Oxygen (O) 47.02 

Silicon (Si) 28.06 

Aluminum (Al.) 8.16 

Iron (Fe) 4.64 

Calcium (Ca) 3.50 

Magnesium (Mg) 2.62 

Sodium (Na) 2.63 

Potassium (K) 2.32 

Phosphorous (P) 09 

Sulphur (S) 07 

Chlorine (CI) trace 

Nitrogen (N) trace 

SILICON. The silicon (Si) never occurs in the free state 
but always combined with oxygen (O) in the form of silica 
(SiOj), which unites with other minerals forming silicates. 



16 Soils of California 

PHOSPHOROUS is present in most soils to the extent of 
five or six parts per million. It is a plant food that is necessary 
to all vegetable growth, promoting especially the activity of bac- 
teria, molds and fungi. In natural mineral phosphates the phos- 
phorous is combined with lime, and as calcium phosphate is as- 
sociated with other minerals to form rock. In artificial fertilizers 
the phosphorous is combined with lime, iron, or aluminum. Some 
phosphates such as bones, which are mainly phosphate of lime, 
also contain organic matter and some nitrogen. Phosphates are 
not easily dissolved and special agents are used to render them 
soluble and useful as soil fertilizers. 

POTASH exists in most soils in varying degrees. That 
which is combined with humus material, or with the hydrated 
silicates is easily set free and easily assimilated as plant food. 
In finely divided silicates such as clay, (silicate of aluminum) 
the potassium becomes active as a plant food in a short time, 
while the potassium in rock debris and sandy soil may be inert 
indefinitely. 

LIME. This occurs in soils principally as calcium carbonate, 
but it is also found combined with the organic matter as humates, 
with sulphuric acid as sulphate (gypsum) and with silica as sili- 
cate of lime. Calcium carbonate, or lime-stone, increases the 
absorption power of soils, and its presence renders the phos- 
phates, potash, and nitrogen more readily soluble. Its value 
is not so much for plant food as for its efifect upon the physical 
properties of the soil. It binds the particles of sandy soil together, 
increasing its water-holding capacity. It helps to granulate clay 
soils, and stimulates bacterial activity. It neutralizes acids and 
renders harmless some toxic substances. It helps, under favor- 
able moisture conditions, to humify the soil, giving it the dark 
color so pleasing to the farmer, as it generally denotes the pres- 
ence of humus and means fertility. 

When lime is added to muddy water the solids settle to the 
bottom in light flufify groups of floccules, and a clear liquid is 
left above. This is called floccnlation. Mineral acids and most 
fertilizing material also possess this property : while alkalies pre- 
vent and break up flocculation. Soils rich in lime are well gran- 
ulated and maintain a much better physical condition than soils 
of the same texture which are poor in lime contents. Large 
amounts of lime or heavy clay soils have made them much lighter. 



Soil Forming Material 17 

MAGNESIA. This generally exists in soils in only small 
amounts in the form of the carbonate or the silicate. It is more 
abundant in soils that are derived from mica schists, serpentines, 
etc. It is not a plant food and is not desirable, even exerting a 
toxic effect upon some plants. Limestones, raw or burned, that 
contain magnesia should not therefore be added to soils. 

IRON. This element is universally distributed, existing gen- 
erally as the anhydrous sesquioxide, or as the hydrated sequioxides 
of the silicates. Plants assimilate iron only in small quantities 
but it seems indispensable to their development and to the proper 
functional activity of their assimilating powers. If present in 
more than small quantities it is harmful for common crop plants. 

SULPHUR. This is usually present in humid regions in 
scarcely more than a trace, enough for all common crops except 
onions, which require a fairly large amount. 

CHLORINE AND ALUMINUM are absorbed and used by 
plants, but exist naturally in soils in sufficient quantities to supply 
all demand. 

ELEMENTS FROM THE ATMOSPHERE. Ninety per 
cent of the crop raised comes from the atmosphere and not from 
the earth. The atmosphere provides an inexhaustible supply of 
oxygen, hydrogen and carbon, which are the main food of plants, 
and only ten per cent of the plant food is demanded from the 
minerals. These minerals exist in nearly every soil in sufficient 
quantities to supply the plants with food, and tons of minerals are 
not needed as food, but other material may often be added to soil 
to advantage in order to improve its physical condition. Given 
the proper physical conditions in the soil and crops will grow 
and find all the food they desire as a rule. Nearly all so-called 
wornout soils are simply abused soils, and poisoned soils whose 
physical condition only needs to be restored in order to restore 
their productiveness. It will not do, however, to neglect the 
mineral matter in all cases, small as it is. For example, we find 
in bogs vegetation consisting of species that have little mineral 
in their composition, but we do not find nutritious seeds or fruits 
or valuable fibres or plants with other useful qualities flourishing 
where the vegetable mold is so thick as to prevent the roots from 
reaching the true soil beneath. There must be the admixture of 
organic and mineral matter ,and a good soil atmosphere as well 
as free access to the atmosphere above the soil. 



18 Soils of Cai.ifobnia 

NITROGEN is found chiefly in the form of nitrates, and these 
are very sohible, leaching out of the soils quickly, and cannot 
accumulate in the soils of humid regions. In its free state nitro- 
gen is not directly absorbed into the tissues of growing plants, but 
must be oxidized before it can be assimilated. It is absolutely 
necessary to all plant life, as much so as water, and is one of the 
most costly elements the farmer has to supply. The nitrogen of 
the air is uncombined with oxygen and is unavailable to the plant. 
The conservation and increase of the available nitrogen in the 
soil is most important to the agriculturist. 

Rain and snow bring down a small quantity of available nitro- 
gen from the air, but nearly all the supply contained in the soils 
is derived from combination (oxidation) with the nitrogen of the 
air, or from decaying animal and vegetable matter. 

It is of the greatest economic and biologic value as a plant 
food and may be present in the soil (1) in organic compounds, 
(2) as ammonia, (3) as nitric or nitrous acid, or (4) as amido 
compounds. Each of these four classes may be subdivided chem- 
ically, but that belongs to agricultural chemistry and cannot be 
considered here. The organic nitrogen derived from the debris 
of animal or vegetable life may be in a form easily rendered 
available for plant food, or it may be resistant. The ammonia 
nitrogen is a transition stage arising from decay of incomplete 
nitrification. It may exist as gaseous ammonia or combined with 
mineral or organic acids. The nitrogen may be present as nitrous 
or nitric acid combined with bases, such as nitrate of lime, or ni- 
trate of potash or soda. The amido compounds may exist in 
varying combinations difficult to understand without a good knowl- 
edge of agricultural chemistry. 

The minute bacteria present in all soils convert the nitrogen 
from these various sources into available nitrogen. This process 
does not take place unless the soil is moist and has free air and 
some base such as lime present. Nitrification cannot take place 
unless the soil is in and is kept in the right physical condition. 
Nitrification is most active at summer temperatures, and ceases at 
winter temperatures. There can be no accumulation of soluble 
nitrates in humid climates as there is in the arid and semi-arid 
regions. Soils are unable to hold the soluble nitrates where there 
is an excess of water. The available nitrates must pass at once 
into growing plants, remain in store during dry periods, or be 



Soil Forjiing Material 19 

carried away by the drainage waters from storms or irrigation. 
Some plants, especially those of the leguminous family (beans, 
peas, etc.) permit the development of colonies of bacteria on their 
rootlets which have the faculty of attracting nitrogen from the 
soil air and making it available for plant food. If it were not 
for such agencies the stores of nitrogen would constantly decrease. 
Agricultural biology shows that different types of soils have nitri- 
iynng organisms of different properties, and that they may be iso- 
lated, colonized, cultivated and transplanted. 

CARBONIC DIOXIDE— CO,. This gas furnishes the car- 
bon which is the basis of most plant structures such as wood, cellu- 
lose, starch, sugar, etc., and is the material from which the higher 
plants build their leaves, limbs, trunks and roots. The soil at- 
mosphere contains more carbonic dioxide than the air above, 
hence the soil solution is always charged with more or less 
of the gas greatly increasing its power to dissolve minerals. Soils 
have the power of occluding gases, and this power of absorption 
and holding depends largely upon the physical condition of the 
soil. Soils containing a large per cent of silt or clay absorb more 

than sandy soils. 

Grams Grams Grams 

water ammonia CO 2 

100 grams of quartz absorbs. .0.16 0.11 0.03 

100 grams of clay absorbs.. 2.56 0.72 0.33 

100 g-rams of humus absorbs. 16.01 18.45 2.53 

The diffusion of the carbonic dioxide is dependent upon the 
porosity of the soil, the temperature, and the moisture contents. 
Pressing or impacting the soil, or increasing the water, is fol- 
lowed by decrease of the diffused gas. Diffusion is also less 
where the drainage is poor and the waters percolate slowly. The 
percentage of organic matter in excess does not indicate the per 
cent of carbon dioxide present. The gas may come from the 
irrigating waters, from the air, from decaying animal or vegetable 
matter through bacterial action, or from fertilizers. 



CHAPTER III 

LAND FORMS 

The description, classification, and correlation of land forms 
is called geomorphology. The earth seems to be solid, stable, and 
fixed to the last degree: yet it is really unstable and ever in mo- 
tion, both as a whole and in all its parts. Astronomy shows that 
the sun, moon, planets and stars are unceasing in their course. 
Chemistry shows that the countless atoms and ions form mole- 
cules only by a ceaseless motion that makes each particle of 
matter, each grain of soil a little cosmos. Molecules of the ele- 
ments make up minerals, aggregations of minerals make up rocks, 
and rocks make up land forms. Geology shows that the earth 
is slowly cooling and contracting and ever adjusting its parts to 
this stress and strain. Lands emerge from the sea, and mountains 
are lifted up only to be at once attacked and slowly destroyed 
by atmospheric agencies. 

A glance at a relief map shows that the earth is not smooth 
but has an irregular surface of relief and depression forming hills 
and hollows of all sizes and shapes. These are known as land 
forms made by tearing down the rocks that make the high places, 
and the filling up of the hollows and low places, and covering the 
flats with soil. Each type of land form has its ow^n type of soil, 
for similar causes give similar effects. 

PLAINS, or lowlands, are broad, smooth, level, or gently 
sloping tracts of land not far above sea level. They are generally 
overspread with a deep layer of mantle rock brought down from 
the higher lands by streams and winds, or produced by the decay 
of the bedrock beneath. The term is loosely used, for tlicre are 
hilly and rolling plains as well as level ones, high as well as low, 
and small as well as large. 

STRUCTURAL PLAINS. Most plains are underlaid by 
undisturbed sedimentary rocks, and the flat surface conforms to 
the flat lying rocks beneath. 

COASTAL PLAINS, or former marginal sea bottoms, are 
formed by the slow rising of the sea bottom, and are covered with 



Land Fobms 21 

imperfectly consolidated sediments which have been washed down 
from the older lands and deposited oflf shore. Coastal plains may 
be recent additions to the continent and are geologically said to be 
young; or they may be old and occuring in the interior of the con- 
tinent far from any ocean of today. They may be peneplains, 
the result of the filling of sea borders by wash from adjacent 
mountains, or high lands, as the coastal plains of southern 
California. 

DEGRADED PLAINS were once high, rough regions that 
have been worn down to flatness and low elevation by erosion, the 
work of weather, streams, glaciers, etc. They are seldom as 
smooth as coastal plains, but are studded with low rounded hills, 
due to their material being harder. These are called zvorn down 
plains or plains of degradation. 

ALLUVIAL PLAINS. Large rivers in times of high water 
spread over the adjoining country and deposit coats of sand and 
mud, building up what are known as flood plains. The flood plain 
formed at the mouth of a river where it drops the load of sedi- 
ment that it has carried is called a delta, as the delta of the Colo- 
rado River. 

LAKE PLAIN. Streams in time fill up lake basins with sedi- 
ments converting them into an almost perfectly flat lake plain or 
lacHstritie plain. Lake Tulare is slowly evaporating and being 
filled up and converted into a lacustrine plain. Many farms and 
ranches in the state are being cultivated where lake waters once 
stood. 

GLACIAL PLAINS. The ice sheets that once covered the 
Sierras melted and deposited vast sheets of mantle rock called 
glacial drift which filled up the irregularities of the surface, form- 
ing glacial plains or drift plains. Such plains are of minor extent 
and importance in California but may be studied in the Sierras 
and in the northern portion of the state. 

EOLIAN PLAINS. In the arid regions, misnamed deserts, 
the loose mantle rock is lifted, drifted, and carried away by the 
winds, producing a zvorn-down plain studded with knobs of resist- 
ant rock called wind-zvorn rocks, and the materials accumulate on 
neighboring lands forming a mantle of fine sands. Both the wind- 
worn, and the wind-filled plains are called eolian plains. 
PLATEAUS. A plateau is relatively an elevated area of 



22 Soils of California 

comparatively flat land. There is, however, no fixed line between 
plains and plateaus, for in a region of low relief like the east, 
a broad, massive, high plain at an elevation above 1000 feet may 
be called a plateau ; while in a region of high relief like California, 
the same name would scarcely apply to anything at an elevation 
less than 2000 feet above sea level. Low plateaus may be called 
uplands, and higher plateaus called highlands. They may be as 
smooth and level as a plain, but are usually more broken, and 
some are deeply trenched with valleys. 

MOUNTAIN. A mountain is an elevation rising prominently 
above the surrounding area. Mountain ranges are long, narrow 
ridges of great height, caused by the upheaval of the earth's 
crust, but their forms are due chiefly to erosion. Isolated moun- 
tains that do not form part of a range, are either remnants left 
by erosion, or they may be of volcanic origin. 

HILLS are little mountains. In a region of low relief, hills 
1000 feet high may be called mountains, as in Pennsylvania, but 
in a region of high relief like California, ridges 2000 feet high 
are often called hills ; for example, the foothills of the Sierras. 
Hills are often due to the cutting out of the valleys between them, 
or to the heaping up of the mantle rock, by ice sheets, winds, 
etc. ; hence they may be hills of erosion, or hills of accuuuilation. 

VALLEYS. These are the most common of relief forms. 
Many of them have been made wholly or partially by running 
water. Valleys that lie between mountain ranges are called inter- 
mont valleys. Those formed by the arching down or synclinal 
formation of the bedrock are known as structural valleys: thus 
the Great Valley of California is both an intermont and a structual 
valley. 

BASINS are areas of deficient drainage, having no outlet to 
the sea, hence the water must be retained until evaporated. 
BOTTOM LANDS are built up by long continued deposition 
of river sediments to a considerable height above the adjacent 
lower valley plain. 

BASE LEVEL. This is the plain below which erosion can- 
not ])roceed, the final base level being sea level. There may be a 
number of local base levels determined by the outlet of each 
stream, but only one general base level. The base level is not a 
topographic form but a mathematical plane which may or may 



Land Forms 23 

not, and generally does not, coincide with a land surface. A 
base leveled surface is any land surface, however small, which 
has been brought approximately to a base by gradation. If the 
area is large it is a base leveled plain. A peneplain is one which 
has in general been reduced to a base leveled plain, but also con- 
tains some unreduced residual areas. 

BROKEN BLOCK LANDS. In some regions the earth'a 
crust has been broken into blocks by nearly vertical cracks, very 
much as an ice field is broken into cakes. These blocks have been 
displaced, some upward, some downward, and others tilted on 
one side, just as ice is tilted. The cracks are called faults. The 
elevated block may form steep sided table lands, and if tilted 
they form sharp crested ridges, but if depressed they may form 
basin or rift-valleys. The Sierra Nevada is a faulted block and 
the eastern side has been tilted up, forming a short steep slope, 
while the west side is long and slopes at a low angle. Many cf 
the ranges of the Great Basin are tilted blocks, and the Island 
of San Clemente is a good example. The subsidence of a long 
narrow block between two or more fault lines produces rift val- 
leys such as the one commonly known as Death Valley, between 
the Panamint and Funeral ranges, a part of its surface being be- 
low sea level. 

VOLCANIC LANDS. Volcanic eruptions produce a relief 
of conical and dome elevations standing singly or in groups, as may 
be seen at Mt. Shasta or at Lassen's Peak. Streams of lava flow- 
ing from the vents have flooded thousands of square miles to a 
great depth, building up lava plateaus with a comparatively 
smooth surface, as in the northeast corner of the state. Volcanic 
action is constructive more than destructive, and is a great build- 
er of relief land forms. Lava beds weather and crumble into 
rich soil of great agricultural importance, and volcanic dust, mis- 
called ashes, is carried by the winds broadcast over the land, re- 
newing the soils. Volcanic matter may be fluid, filling and chok- 
ing original river valleys, or covering plains with a flood of mol- 
ten rock. Good illustrations of this are common in the great 
placer regions of the Sierras. The molten matter may be blown 
to fragments by the escaping steam, forming showers of so- 
called ashes which cover the earth like sand. This volcanic ash 
is very light and the particles cohere readily, and the decay is 
slow at first and then rapid. They are easily washed away by 



24 Soils of Caiifobnia 

rains. While they seem to be glassy they contain considerable 
amounts of lime, potash, soda and iron, which are added to the 
soils. As shown elsewhere, volcanoes have added largely to the 
agricultural wealth of this state. 

ECONOMIC. Alluvial, lacustrine and glacial plains are the 
best agricultural regions in the world on account of the depth and 
fertility of the soils. Coastal plains come next in value, except 
where irrigation places them in the front rank. Worndown plains 
are often useless for agriculture on account of the shallowness of 
the soil, but they sometimes support forests. Eolian plains are gen- 
erally arid regions, not on account of lack of fertility in the soil, 
for they are exceptionally fertile, but for lack of water for irri- 
gation. Plateaus are less favorable for agriculture on account of 
the rougher surface, poorer soil, and colder climate. The soil on 
mountain slopes is thin and poor often, and there are large areas 
of bare rock ; the climate may be severe, and the seasons short. 
Agriculture is impossible high up in the mountains except in some 
of the sheltered valleys. Mountains are the great soil factories 
where the bedrock is rapidly broken up and carred away by the 
streams to renew the soil in the valleys and on the plains below. 



PART II 
CHAPTER IV 
PROCESSES 

In order to trace the erosion, drainage development, and 
origin of the present land forms, and of the soil that covers them 
we must study the processes by which these forms have been de- 
veloped and the agencies used. This study is known as geomor- 
phogeny. 

VIRGIN SOIL. If we take up a handful of soil and examine 
it the eye alone shows that it is made up of bits of matter, decayed 
leaves and twigs, blackish mold and stony particles of various sizes 
and shapes. Under the microscope we see that decay is breaking 
up these stony particles along their edges, joints and cleavages. 
The soil particles are ever being broken up into still finer states 
of division. Mountains are destroyed, hills disappear, valleys are 
filled up by agencies that seem at first to be wholly destructive. 
The very processes that we call destructive, however, and associ- 
ate with death, are in fact constructive and associated with life. 
They are but changes, steps forward, not backward, which bring 
matter from the lower mineral state up to the higher condition 
of soil and ready to take the next upward step into plants and 
animals, into organic living forms. 

The physical properties of soils depend upon the processes 
by which they were formed, and we must know these processes in 
order to classify the soils, as their classification is necessarily 
linked with their derivation. Changes in the underlying material, 
in the rocks or subsoil below, are largely responsible for the many 
varieties of soils known ; and the processes which gave this mate- 
rial its present character determine the class to which the soil be- 
longs. The factors involved in the processes vary with the climate, 
so that soils formed under arid, semi-arid, or subhumid condi- 
tions are always dififerent from those occuring in regions of heavy 
rainfall. The soils in a region of low rainfall always contain a 
larger per cent of soluble material than those of the more humid 
regions, but lack the irrigating waters to make them available. 



26 Soils of California 

THE ATMOSPHERE acts directly in forming soils (1) as 
a mechanical agent, (2) as a chemical agent, (3) it furnishes 
the conditions under which the sun produces temperature, (4) 
it controls evaporation and precipitation. 

WIND EROSION is the mechanical action of the atmosphere. 
Rocks are worn away and converted into soil by the abrasion 
and impact of wind-blown dust and sand. In the arid regions, 
cliffs, hills and ranges are worn away by the sand blasts. 
CHEMICAL WORK OF THE ATMOSPHERE. The im- 
portant chemical changes wrought by this agency, generally in 
connection with water, are oxidation, carbonation and hydration. 
Iron salts are oxidized and color the soils red, and other salts are 
slowly oxidized or converted into carbonates. Water dissolves 
salts in the soils and the solution is drawn to the surface by 
capillary action where the salts are left in a hydrated condition. 
Agricultural chemistry is largely a study of the myriad forms 
of these chemical changes. 

DUST is an example of the mechanical action of the atmos- 
phere. A feeble wind moves particles of dust, a moderate stiff 
breeze shifts dry sand, and a very strong wind moves small peb- 
bles. Beds of volcanic dust thirty feet deep occur in Kansas 
and Nebraska, hundreds of miles from the nearest known vol- 
canic vents, and the material has evidently been carried there 
by the winds. Many of the soils of California are rich from this 
wind-transported volcanic dust. Much of the famous loess de- 
posits are evidently eolian. Dust forms films and layers every- 
where, even on the bottoms of lakes, and is ever taking from or 
bringing to the soils some material every year. 
DUNES. The winds do not often lift sand far above the sur- 
face of the land but move it along and raise it into mounds and 
ridges, like drifted snow, which are known as sandnncs. These 
dunes sometimes invade fertile lands causing great loss unless 
checked. On the other hand this sand often does great good, 
for blown onto clay soil and silt soil it gives them a loamy char- 
acter and improves them. 

TEMPERATURE. The daily range of the temperature is 
influenced (1) by the latitude, '(2) by the altitude, and (3) by 
the humidity. The lightness and dryness of the air at high alti- 
tude allows the heat to radiate rapidly at night and the nights are 
cool or cold. The rocks expand under the heat of the day and 



Pbocesses 27 

contract under the cold of the night, causing the surface to crack 
and scale off, forming heaps of debris at the feet of the cHffs. 
The expansion and contraction of such chffs as those of the Yo- 
semite is far greater than the uninformed would think possible. 

High temperatures favor chemical action and rocks weather 
faster in regions of abundant moisture and high temperatures. 
The rocks of the foothills below Mt. Shasta weather much faster 
than the rocks in the arid portions along the Colorado River, A 
moist climate favors the growth of vegetation and its decay sup- 
plies organic acids to increase the solvent powers of the waters ; 
thus the rocks of the tropics are decomposed to greater depths 
than those of the northern latitudes. A moist atmosphere favors 
oxidation, carbonation and hydration and the greater growth of 
vegetation, which in turn promotes rock-weathering and soil- 
forming. 

Lands sloping toward the sun are warmer than those sloping 
away from it, as the south side of a hill is warmer than the north 
side. Dark colored soils absorb more heat than light colored soils 
and retain it longer. 

The temperature of a soil is raised by fermentation and decay 
of vegetation and animal matter, a fact taken advantage of by 
those who raise mushrooms. While these factors affect the char- 
acter of the soil, the temperature of the soil in turn affects greatly 
its adaptability to crops. Few seed will germinate if the soil tem- 
perature is below 45 degrees F, and from 65 to 100 degrees F is 
more favorable. Gravelly and sandy soils are warmer than clays. 
Wet soils are cold because much of the heat received from the 
sun is used in evaporating the water ; hence soils are warmed by 
draining them. 

WEATHERING OF ROCKS. Bedrock exposed to the 
weather, that is to the action of sun, air, and water, is decomposed 
into rock waste or loose material. The oxygen of the air attacks 
some of the rock minerals, oxydizing them, as when iron is oxi- 
dized, or rusted, and falls into a red powder. The carbonic acid 
gas of the air combines with lime forming carbonate of lime, 
which is dissolved by water and carried away. Rocks expand 
under the heat of the sun by day and contract by night, cracking, 
peeling and scaling. Water drains into the cracks by day and 
freezes at night in the cracks and pores, splitting the rocks. Sands 
blown by the winds erode them, or lodge in the crevices and fur- 



28 Soils of California 

nish a soil that plants grow in only in turn to attack the rock. 
Roots penetrate the minutest crevices, and, growing, crack and 
split the rocks, and the vegetable acids secreted by plants dissolve 
the minerals. Water dissolves out caves and undermines cliffs. 
Ice and snow shove and push rocks from their places. 

The combination of these and other destructive processes is 
called zvcathcring, and the products are sand, clay, gravel, pebbles, 
boulders, silt and soil. 

WATER plays the most important part of any single substance 
entering into the structure of the earth. It has the widest dis- 
tribution and is everywhere in relatively rapid motion. In the 
gaseous form it escapes from the bosom of the ocean, from the 
surface of the soil, from the foliage of vegetation, and from the 
bodies of animals, to rise to varying heights above the surface 
of the earth and to be precipitated as rain, hail or snow. It is 
the constant evaporation of water from the sea and its return 
to the land and the leachings of the soil that keep both the soil 
and the water at the standard of purity which is essential to all 
the life of the land areas. 

RUN OFF. A part of the rainfall sinks below the surface 
into drainage channels or is absorbed by the soil and rock mantle. 
A part runs off the surface at once, and a part is evaporated. 
The water that does not sink into the ground but flows away is 
called the run off. The ratio of the run off to the rainfall varies 
with the slope of the land, its relief, geologic structure, climate 
and vegetation. The steeper the slopes, the more rapid the rain- 
fall, the less porous the soil, and the less the vegetation, the more 
water will run off without sinking beneath the surface. 

MECHANICAL WORK OF WATER. The rain washes the 
atmosphere, carrying down dust, smoke and gases onto the soil. 
Some of these gases, such as the carbon dioxide (COo), dissolve 
mineral matter in the rocks and soils. Clayey soils baked by the 
sun are softened by the rain and are then easily removed by run- 
ning water. The expansion and contraction caused by alternate 
wetting and drying cause the soils on slopes to creep downward. 
This is called soil creep. When rain falls on dry sand or dust 
the cohesion of the particles is increased and shifting by the wind 
is checked for a time. Drops of water fall with a certain force 
which may seem of slight importance but which is really of great 



Pbocesses 29 

moment. In a heavy rain, drops cut clods to pieces rapidly. A 
flat stone may protect the soil and be left at the top of a little 
mound of earth, or even form the top of a large pinnacle in the 
course of time. 

Rain drops have a disrupting effect that promotes the rapid 
washing of the soils. The first efifect of erosion by water is to 
roughen the surface by cutting valleys, and leaving ridges. The 
final effect is to make all smooth again by leveling the ridges and 
hills and filling up the valleys and hollows. On bare mountains 
the heavy rains wash the soil down to lower elevations. Brush 
and forest prevent the rain from cutting the soil to pieces and 
from spreading in sheets and washing the soil away. 

SOLVENT ACTION OF WATER. All waters, rain or 
spring water, contain more or less mineral matter in solution. 
Hard or soft water means that the water has much or little car- 
bonate or sulfate of lime or of magnesia in it. This dissolved 
mineral matter is left wherever the water evaporates. Water 
containing carbon dioxide is a strong solvent of the carbonate and 
phosphate of lime and of the salts of magnesia and iron. 

Decaying vegetation acts upon rocks through the carbon diox- 
ide set free. Decay of nitrogenous matter gives rise to nitric acid, 
which dissolves mineral matter in the soil. Soils formed in the 
arid regions where the solvent action of the water is small are 
distinctly sandy and the particles are sharp. Soils formed under 
subhumid to semi-arid conditions always vary from those in the 
humid regions. In the regions of heavy rainfall the more soluble 
materials are leached out by the carbonated waters, leaving the 
more siliceous matter. The soils of the drier climates retain 
and contain therefore a larger percent of soluble material and 
wait only for irrigating waters to make this material available 
for crops. 

STORAGE OF WATER. When sediments are laid down in 
the ocean, or in gulfs and bays, there is locked up in them large 
volumes of water varying from 25 to 50 per cent of the volume 
of the sediment, according as the pore space is large or small. 
All rocks contain more or less water, even hard marble absorbing 
0.23 per cent of its weight. The storage capacity of soil generally 
is in round numbers two feet of water to five feet of soil. Sand 
and sandstones lying below drainage outlets may contain as high 
as 38 per cent of their volume of water, and become storage res- 



30 Soils of California 

ervoirs of great capacity. Clays range from 20 to 40 or even 
50 per cent of their dry weight in stored water. 

AIR RETAINED. The capacity of water to retain air con- 
densed within itself increases with the air pressure to which it is 
subjected. Air does not readily escape from the spaces of a fine 
grained soil, especially when the soil is saturated with water. 

ICE BENEATH THE SURFACE. The water which freezes 
within the soil has an efifect upon the surface. Stones and boul- 
ders work up through the soil as freezing and thawing alternate. 
The frozen water in the soil makes it solid and prevents surface 
erosion. If the water in ponds, streams and lakes is shallow the 
water freezes to the sand and gravel and boulders at the bottom, 
loosening and moving them. 

WORK OF UNDERGROUND WATER. Rain water is 
pure, but water from wells and springs contains mineral matter, 
showing that the rain water after sinking underground has dis- 
solved mineral matter. One mineral in solution may be exchanged 
for another, the lime carbonate of a shell may be removed par- 
ticle by particle, and some other mineral such as silica be left in 
its place ; or cementing material may be deposited in a soil, form- 
ing a hardpan. Materials taken from rocks in one place may be 
added to a soil in another place. Rock minerals in one place 
may be made porous, making the soil lighter ; and in another place 
the pores of. the soil may be closed, indurating or hardening the 
soil. New minerals are developed out of the old by addition, 
subtraction, or division of the minerals. In fact the mantle rock 
of soil and subsoil represents the residium of this working over 
of the material from the bedrock, or of the original material 
before it is transported to the soil area where it remains. 

The underground water moves large masses of material at 
times. It saturates masses of earth and rock, increasing the 
weight and destroying the adhesion between layers, as where rock 
or soil rests on clay, and masses give way, forming landslides. 
Streams of stones moving steadily but very slowly down steep 
slopes are a form of slide called screes. At the foot of cliffs and 
steep slopes there is generally a talus, or heap of rock fragments 
fallen from above. 

DRAINAGE. When a land surface is young, or recently ele- 
vated above the sea, the run-off fills the depressions, forming 



Processes 31 

lakes, ponds and marshes. On the low plains, drainage develops 
slowly and remains imperfect for a long time. The shallow lakes 
of the glacial drift high in the Sierras are being slowly filled with 
mud and peat which will form soils there in the future. 

The diameter of the soil grains and the amount and form 
of the pore spaces determine the amount of water which can 
pass through a soil in a unit of time. The pore spaces are deter- 
mined by both the size and the arrangement of the soil par- 
ticles, and may vary from 25 to 45 per cent of the volume of 
the soil. Underdrainage removes water from all except the 
capillary spaces and leaves the other spaces free to air circulation. 
There is also an upward movement of the air from the drains to 
the surface which aids in the aeration of the soil. Seepage is the 
movement of water through the fine pores of the soil under the 
stress of gravitation. It begins when water enters the soil and 
ends where the water escapes into passages larger than capillary. 
The moving power is the hydrostatic pressure of the water itself, 
and this pressure is increased or lowered according to the pressure 
of the atmosphere, varying with high and low barometer. The 
flow of water from tile drains will vary as much as 15 per cent 
with the barometric changes. 

GRADATION. The run-off forms streams, and a stream in 
times of flood cuts its channel deeper, and the overflow deposits 
sediment on the adjoining floodplain. In other words the stream 
in flood degrades or scours its channel, aggrades or fills up its 
plain. As a result of its varying velocities in flood and in low 
water, a stream may deposit coarse material at one time, and fine 
material at another. Floodplain deposits, or soils, therefore vary 
from the finest mud, through sand and gravel to boulders. When 
a rough piece of land is prepared for irrigation it is graded by 
cutting down the high places and filling up the low. The same 
process is going on all over the world, mountains, plateaus, and 
hills are being worn down and the material deposited in valleys, 
basins and over the lower plains. Lowering the level of the land 
is called degradation, and raising the level is called aggradation, 
while the result of the two processes is called gradation. As a 
country grows smoother and is reduced by gradation to a plain of 
low relief, not far above sea level, it is called a peneplain (almost 
a plain). Young low plains are smooth and gently sloping, easily 
accessible, easily cultivated and generally productive. 



32 Soils of Califobnia 

STREAMS- If any stream is followed up it is found to divide 
into smaller branches and rivulets, as a tree divides above the 
trunk into branches and twigs. Take any of the rivers for ex- 
ample. Near its source in the high Sierras the slopes are steep, 
the current swift, the channel narrow or canyon like, and are filled 
with boulders : lower dow^n the slope is more gentle and the water 
course consists of a wide outer valley which the stream covers only 
at high water, and a narrower channel winding irregularly from 
side to side; still lower the valley becomes very much wider and 
consists of an extensive floodplain, and the channel follows a 
meandering course full of bends and horseshoe curves ; and finally 
the river reaches the sea through a delta or a series of sloughs 
and bayous. 

TRANSPORTATION OF SEDIMENT. We generally 
think of a stream as a stream of water only. It is also a stream 
of mantle rock or soil held in suspensioji. Streams are the circu- 
lation system of the earth, carrying nourishment to all parts. In 
the human system the blood goes from the heart and carries in 
suspension the digested foods to all parts and picks up and carries 
away used-up products, until the life-giving stream is overloaded. 
Then it passes into the lungs and the impurities are burnt out by 
the oxygen of the air. The rains descend upon the mountains 
and form streams that take up soil material, plant food, and car- 
ries this down and distributes it where it is needed, and also picks 
up its loads of used material, or waste, until overloaded it dumps 
itself into the ocean where the waste material is washed out. 

The ocean is the great septic tank of the world. Here waste 
material is deposited to form sediments or soils for generations 
yet to come. Evaporation carries the pure water up to the clouds 
and back to the mountains, to be precipitated again, completing the 
cycle of the waters. 

Thus the surface of the earth, the soil, is the growing, living, 
changing part with its circulation system that is analagous to the 
blood of animals and the sap of vegetation . 

The size of the rock particles which a stream can carry in 
suspension increase as the speed of the current increases. A cur- 
rent of one-third of a mile per hour can carry clay; two-thirds 
an hour can carry sand ; two miles per hour, pebbles the size of 
a bean ; four miles an hour, stones the size of an egg ; while a 
mountain torrent will move huge boulders. 



Pbocesses 33 

A stream carrying all the sediment it can is said to be loaded, 
or it may become overloaded and have to deposit some of its 
burden. 

DEPOSITION. A stream flowing down a steep hill or moun- 
tain side erodes a gully, or canyon, and deposits at the mouth of 
a gully a conical or fan-shaped heap forming an alluvial cone, or 
flat fan. 

Illustrations of this may be seen on a small scale anywhere 
after a rain. 

The rivers descending from the great Sierras build extensive 
fans at the base of the range, such as that of the Merced River 
which has a fan with a radius of 50 miles. Where the alluvial 
fans are so large as to join, forming a continuous plain, such as 
are found all along the east side of the San Joaquin Valley, or the 
base of the Sierra Madre, it is called a piedmont (foot of the 
mountain) alluvial plain. These are easily irrigated as the water 
spreads naturally over the land and can be easily carried to any 
part. When a stream overflows its banks it deposits sediment on 
the flooded ground forming an alluvial plain. At the mouth of 
the river the alluvial plain extends into the lake or sea, forming 
a delta. At the head of the delta the stream often divides into 
distributaires and enters the sea or lake by many mouths. The 
soil of a flood plain, or of a delta, is often so fertile that it pays 
to protect it by dikes. Streams towards their mouths may become 
overloaded with sediment, the channels become shallow and 
crooked and constantly changing and in some cases the river be- 
comes divided into a network of small streams and is said to be 
braided. 

RECENT STREAM DEPOSITS. With every heavy rain 
the streams traversing the foothill valleys become heavily laden 
with sediments washed from the surface of the bordering slopes. 
Upon entering the valley, the streams overflow their banks, the 
water spreads, the velocity of the current is suddenly checked, 
and the coarser sediments, consisting say of fine sands and silts, 
are deposited, covering the original material of the valley slopes 
with a thin layer. In this way some of the streams have built up 
along their flood plains a slight ridge, the summits of which they 
traverse, until the slopes of the stream beds reach a minimum, 
when they break through the enclosing ridge, seek new channels, 
and build up other low broad ridges. These streams finally enter 



34 Soils of California 

the valley trough where the drainage is deficient and water fre- 
quently stands during the rainy season, and it is here that the finer 
silts and clays are deposited. 

CROOKEDNESS OF STREAMS. The current of a wind- 
ing stream is swifter on the outside of the bend, and it cuts the 
bank there and deepens the channel. The slower current on the 
inside of the bend drops its part of the load, building up a bar of 
mud or sand. 

VALLEY FORMS. A swift stream uses the sand and gravel 
it carries as tools that saw their way down through the hardest 
rocks. Thus the region through which the Colorado River runs 
in Colorado and Arizona is slowly rising, and the river cuts its 
way down, ever deepening its canyon. A swift stream cuts the 
bottom faster than the sides, cutting deep narrow valleys such as 
are found in the canyons of the Sierras. A slow stream cannot 
sweep the bottom clear, and winds cutting the sides and wearing 
away its banks, forming in time a wide valley. A stream which is 
actively deepening its valley is young. A stream which has cut its 
valley down so as to smooth out its falls and rapids has reached 
base level and is mature. A stream which has widened its valley 
and aggraded its flood plain has reached old age. 

LEVEES. As a river overflows its banks, the current is 
checked rather suddenly and the larger and coarser sediment is 
dropped near the channel, thus building up a bank above the level 
of the flood plain, forming a natural levee. The floods leave a 
thin layer of fine fertile mud or silt over the submerged land, 
forming a soil of great fertility that is often renewed. 

LAKES. Lakes, ponds and marshes are bodies of standing 
water which occupy depressions in the surface of the land. They 
are never stable, but are ever changing. (1) Waves wear the 
shore and the material from this is assorted and deposited; (2) 
streams carry their loads of mud, sand, and gravel into the lakes 
and leave them there; (3) winds blow in sand and dust; (4) 
animal forms of Hfe live and die there leaving their bones or 
shells; (5) plants grow in the shallow waters and their material 
accumulates on the bottom ; (6) the lake is drained by the cutting 
deeper of the outlet; (7) in cold regions ice crowds the shores 
and eflfect changes; (8) in the arid regions minerals are precipi- 
tated from solution. All this accumulation of material raises 



Processes 35 

the bottom of the lake and reduces the water capacity of the 
basin. If the rainfall exceeds the annual evaporation, and the 
outlet cannot carry off the water the lake increases in size, spreads 
out over more land, but is shallower; plants accumulate, and a 
marsh peat bog, or meadow is formed. Where the sediments 
deposited in the lakes are made up largely of the shells of fresh 
water animals, the calcareous secretions of plants, or lime pre- 
cipitated from solution, such deposits are called marl if they are 
soft. 

In the arid regions where the evaporation exceeds the rain- 
fall, the depressions in the floor of the basins All up with water 
in the wet seasons and evaporate in the dry seasons, leaving bodies 
of salt, soda, borax, etc. These are properly called intermittent 
lakes, but are locally known by many names, such as "dry lake," 
"soda lake," "borax lake," "alkali lake," "desert sink," etc. Gla- 
cial lakes are hollows in the bedrock eroded by moving ice, or 
hollows made by deposits of drift forming dams. Examples are 
numerous in the higher portions of the Sierras. Volcanic lakes 
are old volcanic craters filled with water : or are caused by the 
damming of a stream by a lava flow. 

GLACIERS. These ice streams are slow, stiff and awkward 
compared with a river, but are prominent factors in the making 
of many soils, as they are great soil mixers. A glacier tears loose 
rock fragments at its head, eating slowly into the mountain side, 
forming a vast hollow called a cirque, and the ice stream several 
hundreds of feet in depth grinds the rock underneath into flour 
called bergmeal. The thick accumulations of drift at the end of 
a glacier, or edge of an ice sheet, is the terminal moraine. A gla- 
cier does not have the sorting power of water so that its material 
is a mixture of all kinds of rocks, cobbles, pebbles, sand and clay 
confusedly intermingled from the finest to the coarsest and is 
easily recognized as glacial drift. The land worn down by glacial 
action is left barren bedrock, or with a thin mantle of coarse 
material, rendering agriculture impossible. The vegetation of 
such a soil generally consists of coniferous forest. The bulk of 
glacial drift is composed of boulder clay, a stiff clay containing 
pebbles and boulders. Glacial drift ridges are called marginal 
moraines, formed along the edges of the melting ice sheets, kames 
are the irregular heaps of sediment formed where water escapes 
from the ice, eskers are sharp winding ridges of sand and gravel 



36 Soils of Califobnia 

deposited in stream channels under the ice ; and drumlins are 
lenticular or prismatic hills of clay. Glacial streams are as a rule 
aggrading streams and develop alluvial plains called valley trains, 
or deltas, where they enter lakes, bays, or other streams. 

The soils of California owe much to glacial action, for glaciers 
not long ago covered large portions of the higher ranges, and 
small glaciers still exist on the sides of Mt. Shasta where their 
action in soil forming may be studied. The glacial lakes near 
Lake Tahoe and at the head of the Yosemite Valley give excel- 
lent opportunity to study moraines, kames, eskers, and drumlins. 



CHAPTER V 

CALIFORNIA TOPOGRAPHICAL PROVINCES 

California is the result of the geologic forces of the past, and 
the agencies at work today. It is not to be expected that the geo- 
logic history of all parts of such a vast area are the same. The 
regions or large areas having the same history are known as 
provinces. These provinces may be studied according to their 
relief forms or topography and climate, or according to their geo- 
logic history. Considering first from the topographic standpoint 
we find abundant reasons for its diversity in soils and crops. 

AREA. California lies between the parallels of 32 degrees, 
30 minutes north latitude and 42 degrees, thus stretching through 
nine and a half degrees of latitude. This line on the Atlantic 
coast would reach from Edisto Inlet in South Carolina to Cape 
Cod, Massachusetts. 

The extreme distance from the northwest to the southeast 
corner is 775 miles. The maximum width is 233 miles, and the 
minimum is 148. The total area is 158,360 square miles, of which 
the land area alone is 155,980 square miles. The coast line along 
the Pacific measures 1,200 miles. It is larger than the combined 
areas of New York, Massachusetts, Connecticut, New Jersey, 
Delaware, Maine, Vermont, New Hampshire, and Ohio. If one 
considers the diversity of soils existing in all the states mentioned, 
it is natural to expect so large a state as this to contain a very 
wide range of soils. It is naturally divided into six provinces, 
each of which has some soils not found elsewhere, and other soils 
in common with other portions of the state. 

THE SIERRA NEVADA PROVINCE. The Sierra Nevada 
range is not only longest in the state but it is the highest in the 
United States, forming a gigantic wall along the eastern edge of 
the central portion of the state. In form, it is like an immense 
and irregular lense-shaped table that has been tilted up along its 
eastern edge, showing a bold precipitous face to the desert on 
the east, but sloping as a whole gently towards the Great Valley 
on the west. 



38 Soils of Califobma 

The Range proper terminates on the north near Lassen Peak, 
and on the south at Tejon Pass. The crest Ues close to the eas- 
tern edge and its skyHne is marked by hosts of snow-clad peaks 
towering from 10,000 to 13,000 feet above the sea, culminating 
in Mt. Whitney, 14,502 feet above the sea. 

The rainfall among the peaks ranges from 70 inches in the 
northern part in Sierra County to 60 in Eldorado County, and 50 
in Madera County. It diminishes from this to the rainfall of the 
foothills bordering the great valley on the west. Few realize the 
extent of the great watersheds included in this mighty range, or 
the volume and value of the streams descending from it. The 
following areas were carefully computed by state and national 
engineers, and measure the watersheds from the edges of the 
valleys to the head of the streams. Beginning on the north and 
coming south the tributaries to the Sacramento River from the 
Sierras are as follows : Feather River 3654 square miles, Yuba 
1358, Bear 287, and American 1899. The tributaries to the San 
Joaquin River are : the Consumnes River 580 square miles, Jack- 
son 283, Mokelumne 657, Calaveras 491, Stanislaus 1051, Tu- 
olumne 1501, Merced 1076, Chowchilla 268, head of San Joaquin 
1637, Kings 1742, Kaweah 619, Tule 437, and Kern River 2345 
square miles. 

The San Bernardino, Sierra Madre, and San Jacinto ranges 
are the southern extension of the Sierra Nevadas, and their geo- 
logic history is closely the same. They range from 5000 to 10,- 
000 feet in height, culminating in Mt. San Bernardino (Grayback) 
11,725 above sea level. They are drained by the Los Angeles 
River 568, San Gabriel 512, Santa Ana 1540, Santa Margarita 
731, San Luis Rey 566, San Diego 409, Sweetwater 216, Otay 
145, and the Tia Juana River 499 square miles of watershed. 

The Sierras are covered with the National Forest Reserves 
and are given up to lumber, cattle and sheep industries, with more 
or less farming in some of the valleys. 

THE COAST PROVINCES. The Coast Ranges include all 
of the mountain ranges lying west of the Great Valley and the 
other provinces and extending to the ocean. There is no well 
defined central axis, either topographic or geologic, but the range 
consists of a number of parallel ridges 3000 to 4000 feet high, 
with occasional peaks. The rivers are short and the drainage 
areas much smaller than those of the Sierras. 



Califoenia Topographical Peovinces 39 

The northern Coast Range, or that extending north from San 
Francisco, is drained principally by the Eel River which has a 
basin of 3,552 square miles, the Mattole has 225 square miles, 
the Novo 126, Big 164, Navarro 248, Russian 1515, Gracia 82, 
and Gualala 351. The rainfall varies from 40 inches near the 
coast to 30 inches on the eastern side. While lumber, cattle and 
general farming predominate in the northern portion of the range, 
the central and southern portions are noted for their extensive 
orchards, vineyards, and intensified farming. 

The south Coast Range extends from San Francisco to San 
Diego and is drained by numerous short but important rivers that 
supply water for irrigation. At the south end at San Diego this 
range merges with and forms the foothills of the southern Sierras 
and the rivers are classified with the Sierras. With this excep- 
tion the drainage areas are as follows : Guadalupe River 201 
square miles, Pescadero 80, SaHnas 4714, San Luis Obispo 78, 
Santa Maria 1806, Santa Ynez 836, and Santa Clara 1576 square 
miles. 

The rainfall in the mountains is from 30 to 50 inches, varying 
with elevation. In the foothills it is from 20 to 30 inches ; and 
in the valleys from 10 to 20 inches. The valleys are relatively 
broad and of gentle slope, and in general given over to intensive 
cultivation under irrigation of crops that are specified in connec- 
tion with the soil descriptions. 

THE GREAT VALLEY. One of the most striking features 
of California is the great central valley, some 400 miles long, 
which extends for nearly two thirds the length of the state. It 
lies between the Sierras on the east and the Coast Range on the 
west. The northern portion is drained by the Sacramento River 
and the southern portion by the San Joaquin, the two rivers meet- 
ing close to the point where they empty into San Francisco Bay. 
These rivers are fed by the many large streams already mentioned 
in the Sierra Province. The Coast ranges supply only a small 
amount of water to the valley. The Great Valley is a great 
synclinal trough partially filled with the debris from the gradation 
of the ranges that enclose it. 

The elevation varies from slightly above sea level to below 
mean tide, near the bay, and to about 100 feet above sea level at 
Marysville Buttes, and 800 feet a little ways north of Redding. 
The San Joaquin valley is only 420 feet above sea level at Bakers- 



40 Soils of Caxifobnia 

field. The middle or bottom of the valley is a vast plain without 
rock outcrops, bluff, or terrace, with sluggish streams and tidal 
sloughs. On either side are the uplands, consisting of rolling, 
sloping plains which reach to the foothills. The rainfall at the 
north end in Shasta County is from 30 to 50 inches, decreasing 
towards the south to from 10 to 20 in the central portion, and 
from 20 to 30 inches along the bordering foothills. The crops 
are described in detail in connection with the soils. 

THE GREAT BASIN. This is the western portion of the 
great Cordilleran region that has no outlet to the sea, and extends 
from the foot of the Sierras to the eastern boundary of the state. 
The northern portion is small, covering the region from Honey 
Lake in Plumas County to Goose Lake in Modoc County. The 
southern portion covers most of Mono, Inyo, San Bernardino, 
and Imperial Counties, the eastern portion of Riverside County, 
the northern portion of Los Angeles County, the southeast part 
of Kern County, and a part of the east edge of Ventura County. 
It is not a cup-shaped depression gathering its waters at a com- 
mon center ; neither is it a vast level covered by desert lands. It 
is a broad area of varied surface, valleys, plains, mountains, and 
many independent drainage districts, and contains many important 
communities of prosperous people. Its general elevation in Cali- 
fornia is from 4000 feet above sea level in the northern portion 
to 2000 feet in the southern portion, descending finally to sea 
level and even below. Isolated mountain ranges rise from 2000 
to 3000 feet above the general surface of the basin. Between 
the ranges are smooth valleys, whose alluvial slopes are floors 
built up of debris washed through long ages from the ranges. 
These valleys are generally trough-like, merging enough to assume 
the character of plains. Locally they have been miscalled deserts, 
as the Mojave, Amargosa, and Colorado deserts, the proper name 
being arid districts ; for under irrigation, prosperous communities 
now occupy extensive portions of the former so-called "deserts." 

The lowlands and mountains are generally treeless, except for 
fringes of cottonwoods along the streams and straggling brushlike 
cedar in the mountains. The rainfall averages from 2 to 5 
inches; but the storms result mainly from the irregular and often 
violent local disturbances in the mountains and sooner or later 
the "cloud burst" visits every locality. 

The aridity is most apparent when compared with that of the 



California Topographical Provinces 41 

great plains lying between the Mississippi River and the Appa- 
lachian mountains of the east. On the eastern plains the average 
moisture contents of the air is 69 per cent of that necessary for 
saturation and rainfall : in the Great Basin it is 45 per cent. The 
rainfall of the plains is 43 inches, and that of the Basin from 2 
to 5. The evaporation from the surface of Lake Michigan is a 
layer of water 22 inches deep ; from the Great Basin it is 80 inches 
per year in the north and reaches 150 inches in the south. 

Owen's River Basin is one of the minor divisions of the Great 
Basin. It lies at the eastern foot of the Sierra Nevada in Inyo 
County, just east of the highest peaks in the United States, Mt. 
Whitney (14,502) and Mt. Lyell (13,090), and has a watershed 
of 2630 square miles. While the river is only 125 miles long, it 
is fed by over 40 lateral tributaries which rise from the glacial 
lakelets and marshes along the east crest of the highest Sierras. 
It furnishes not only water for Los Angeles City, but irrigating 
waters for the sloping alluvial plains that are made up largely of 
merged delta fan surfaces. These plains are covered with deep 
granitic alluvial soils which vary from sands to sandy loams. 
The valley is extensively cultivated and is particularly adapted 
to stock raising. The Honey Lake region and north to Goose 
Lake is a plateau region consisting of valleys dotted with sage 
brush and rugged isolated mountains. The general elevation is 
4000 feet, the buttes and local ranges rising from 1000 to 5000 
feet higher. The soils are mainly residual from the lava which 
weathers into a light but very fertile soil. There are large areas 
of cultivated land and still larger stretches of barren lava table 
lands. The Mojave Valley district lies to the north of Mt. San 
Bernardino. The Mojave River is 100 miles long but preserves 
its life by concealment, creeping through the gravel and betray- 
ing its existence only where cross ledges of rock force it to the 
surface. It drains an area of 1470 square miles, of which 251 are 
mountains, 219 foothills and 1000 of arid plains and barren 
buttes. The valley is devoted to alfalfa and farm produce with 
here and there fine orchards. The soils are sands and sandy 
loams, generally micaceous and fairly free from alkali. Antelope, 
Rock Creek and several other subdistricts might be described 
which are within the boundaries of the Basin, but receive irriga- 
tion waters from the great ranges which they border, their soils 
being rich sandy loams and sands, with here and there some ad- 
mixture of the clays. 



42 SoUiS OF Calitobnia 

THE CASCADE PROVINCE. The Cascade Mountains 
form the southern extension of the great lava covered range of 
Oregon, and includes the region from Mt. Shasta east to the 
Great Basin, and south to the Sierra Nevada, just touching the 
extreme north end of the Great Valley. Mt. Shasta, 14,380 feet 
elevation, is the culminating peak, the region descending eastward 
to the plateau of the lakes 4000 feet, and southward to the head 
of the Great Valley, which is about 800 feet above the sea level. 
Nearly all of its drainage enters the north end of the Great Valley 
and runs into the Sacramento River, the tributaries and their 
watersheds being the Pitt River, 4597 square miles ; head of Sacra- 
mento River, 538; McCloud River, 678; Battle Creek, 337; An- 
telope Creek, 129; Mill Creek, 154, and Ditch Creek, 192 square 
miles. The region is heavily timbered and the agricultural por- 
tions small. 

THE KLAMATH PROVINCE. The Klamath mountains 
extend from Oregon south into this State over 200 miles. The 
name includes the local ranges known as the McCloud, Trinity, 
Bully Choop, Scott, Salmon and other mountains, whose geologic 
and soil histories are essentially the same throughout. The prov- 
ince is covered by rugged ranges from 5000 to 10,000 feet high, 
and is accessible only by wagon roads. It is given up mainly to 
mining, timber, cattle and sheep, with some farms in the broader 
valleys. The terraced stream valleys are often more than 2000 
feet deep and range in form from V-shaped canyons to broad, 
flat valleys. The rainfall in the eastern portion is 40 inches, but 
west of the divides increases to 60, and near the coast reaches 
70 inches. Nearly all of the drainage goes to the ocean from the 
Klamath River with its 2468 square miles of drainage area, 
Scott's River, 841 ; Trinity, 930; Smith, 691, and Redwood Creek, 
285 square miles. 



CHAPTER VI. 
CALIFORNIA GEOLOGIC PROVINCES 

The geologic age of any soil, or the age of the rocks from 
which it was derived is only of general interest and not always 
of specific value in determining the adaptability of the soil to 
crops. The classification of soils according to the geologic history, 
however, give us clearer ideas of the origin and therefore the 
character of soils in general, and it is worth while to glance at 
the geologic history of the provinces. 

SIERRA NEVADA PROVINCE. We speak of the hills and 
mountains as everlasting and use them as symbols of permanency. 
Geology, however, teaches us that they, like everything else in 
the universe, have their birth, youth, maturity, old age and death, 
and that their death, like that of everything else, means not an- 
nihilation but change of form and another and a new existence, 
and that ever in the line of advancement and progression in the 
scheme of existence. 

The great Sierra Nevadas of today are young mountains in 
rugged and vigorous condition, doing their work as sky-line guard- 
ians of the fertility of the plains below and their teeming forms of 
life. They catch the moisture rising from the ocean and con- 
dense it into rains and snow and store it among their crags to 
irrigate the soils miles away. They give each rivulet and each 
stream its load of material to carry down and build up new soils 
and renew old ones. They were born during the later part of the 
Jurassic time, but not to their present magnitude. By the end 
of the Cretaceous they had been worn down almost to peneplain. 
In the Eocene and Miocene they were cut and carved by rivers 
having wholly different courses from those that exist today, 
many of them leaving their gold-bearing gravels to pay for the 
opening of the state to the farmer and fruit raiser of today. 
Still later came the final uplift, when the towering crests 
were covered with glaciers, the great soil mills of the earth, 
whose waters fed lakes in basin and valley, where loads of sedi- 
ment were deposited by hard-working streams busy in preparing 
lake, or lacustrine, soils for the coming of mankind. The great 



44 Soils of California 

mass of the Sierras is composed of granitic rocks, flanked in the 
northern and central portion by long parallel belts of Jurassic 
and Triassic slates and shales, and Mississippian limestones, and 
flanked along the foothills at the edge of the Great Valley by 
beds of Miocene and Pliocene sandstones, marls, limestones, 
tuffs, clays, and shales ; the whole spotted here and there with 
lavas ancient and recent. 

The geologic history of the Sierra Madre, San Bernardino 
and San Jacinto ranges and the rocks forming them is essentially 
the same as that of the Sierra Nevada and they are included in 
that province. 

GREAT VALLEY PROVINCE. In its earlier geologic his- 
tory the Great Valley has not always drained into the ocean by 
way of San Francisco Bay. There is geologic evidence that it 
has at other times emptied into the ocean at points farther south, 
and it was not until later that faulting broke the mountains and 
formed the Golden Gate. In earlier geologic times the valley was 
submerged by the waters of a great inland lake, or by an arm of 
the sea. The gradation of the Sierras laid down a vast quantity 
of materials filling the valley to great depths. The great rivers 
of the Sierras brought down sands worn from granite, quartz, 
porphyry and lava and emptied them into the lake. These were 
carried by the currents and distributed along the shores and over 
the bed of the lake and deposited as stratified clays, sand and 
gravel, or as beaches composed of gravel mixed with finer ma- 
terial. Still later the land was elevated and the more or less con- 
solidated accumulations were exposed to new weathering and 
erosion. Great c|uantities of material were removed, leaving the 
greater thickness of the beds along the edges and more elevated 
slopes of the valley, often as rounded foothills of ferruginous and 
calcareous conglomerates, partially weathered shales, interstrati- 
fied with sand and silt. The subsequent weathering of this ma- 
terial has given rise to residual soils along the foothills. 

Some of this residual material, through the action of grav- 
ity, or from heavy rains, has slid, or rolled, or been washed short 
distances and accumulated as colluvial soils on the lower slopes. 
More erosion has carried the finer portions of the deposits over 
the valley slopes and along the flood plains of the larger streams, 
forming alluvial soil. 

The intermediate upland plains receive loams, clays, and clay 



California Geologic Provinces 45 

adobes. The flood plains sandy and silty materials, and the river 
bottoms and lowest plains receive deep fine alluvial sands, silts, 
and clays. Naturally soils so formed shade into each other, the 
boundaries being obliterated by recent modifying agencies of wind 
and water. Each soil is subjected to considerable local variation 
in color, texture, and crop value according to the local conditions 
of wind, rainfall, and material on or away from the land, or 
washed on to it from adjacent soils. 

COAST RANGE PROVINCE. The Coast Ranges consist of 
mountains that are roughly parallel anticlines, their corre- 
sponding synclines forming the valleys. The formations north 
of San Francisco consist mainly of Jurassic rocks in the interior, 
and Cretaceous rocks next to the coast. South of San Francisco 
the ranges are mainly Miocene and Pliocene formations with 
some Cretaceous and Jurassic. The rocks are mainly shales and 
sandstones with occasional igneous rocks. Residual soils were 
first formed from these rocks, and are found on the ranges and 
higher foothills. This was followed by the creeping of coUuvial 
soils down the slopes, and the washing of alluvial soils over the 
flats. The shales have imparted a somewhat heavy character 
to the soils through weathering into silts and clays, but the sand- 
stones have relieved and lightened the soils by the sands washed 
or blown into them. 

GREAT BASIN PROVINCE. This great arid region is a 
closed basin into which the rainfall drains to the lowest depres- 
sions and then evaporates. This action leaches the soils and the 
minerals dissolved out accumulate in the low depressions, form- 
ing deposits of soda, salt, borax, etc. The basin is occupied by 
many mountain ranges, most of which dip westerly. The type of 
structure is that of the faulted monocline, or block tilted up at one 
edge or corner. Many of the ranges are formed of pre-Cambrian 
granites and schists, and show along their flanks exposures of 
Cambrian, Ordovician, Silurian, and Devonian rocks. Most of 
the valleys between the ranges are covered with eolian sands. 
Extensive areas are covered with Tertiary or later lavas. All 
these rocks give rise to vast areas of arid, rough, stony soils not 
suited to agriculture and therefore not mapped or classified by 
the U. S. Bureau of Soils. Certain areas close to the flanks of 
the main range, such as the Owens Valley, Antelope Valley. 
Mojave Valley, and the Imperial region are exceptions, as they 



46 Soils of California 

receive more rainfall, and water can be brought from the moun- 
tains and rivers for irrigation. 

The Great Basin is, however, of as great importance to the 
state in general as is a good furnace to the equipment of a palace. 
It is the place where the atmosphere is quickly heated in the day- 
time and rising tends to create a vacuum towards which the mois- 
ture-laden winds of the ocean flow, giving the rains in the moun- 
tains, and the cool invigorating breezes to the coast lands and to 
the Great Valley. The periodic changes of climate in the ages 
past are recorded in the Great Basin in the rise and fall of former 
great lakes, such as the lakes known to the geologists as Pa Ute 
Lake, Lake Lahontan. and others. Their terraces still exist, show- 
ing various periods of increasing and decreasing rainfall and 
evaporation, each of which meant soil building under varying 
conditions. 

CASCADE PROVINCE. The Cascade mountains form the 
southern extension of the great lava covered range of Oregon 
that comes south a short distance into this state. This range in 
Oregon shows the underlying core of granites and slates of the 
Jurassic time, and the heavy limestones of the Carboniferous, 
similar to the Sierra Province. In California, however, lavas 
and other effusives of the Tertiary and later times cover most of 
the country within this province. The residual and colluvial soils 
from the lava are rich in plant food, and where water can be ob- 
tained produce crops in abundance. 

KLAMATH PROVINCE. This region is made up of forma- 
tions older than those of the Sierras. Rocks of the Cambrian, De- 
vonian, and Mississippian and other periods of the Paleozoic age 
have been identified, flanked on the south by the Comanchean and 
Jurassic. It was reduced in Cretaceous time to a peneplain, and is 
now a high mountain plateau rejuvenated by late uplifts, the 
rivers deepening and widening their channels. It shows the ef- 
fect of glacial action and lava flows. The soils of the valleys are 
sands and gravels mixed with silts and clays. 



PART III 

CHAPTER VII. 
SOIL CLASSIFICATION NECESSARY 

COMMON NAMES ARE MISLEADING 

It has been a recognized fact since the dawn of history that 
soils differ, and many names have been given them. Many of 
the names in common use have a local value only and are mislead- 
ing when used away from their home locality. Most of them 
should be used simply as descriptive adjectives, as they are use- 
less as names for scientific comparison and correlation of soils. 
A single soil may have several local names in the same state, and 
the common name is often given totally different soils in different 
states. This confusion in names often means loss of time and 
money, and sore disappointment to new settlers. A large number 
of common names are mere nicknames, quite appropriate in the 
region where they originate, but wholly misleading and mischiev- 
ous when transplanted to regions having different climates, dif- 
ferent geologic formations, and different local conditions. A 
little examination into soil names in common use will show 
the necessity of having standard methods for classifying, com- 
paring, and naming soils, such as that adopted by the U. S. Bu- 
reau of Soils. For example, this bureau has named a soil in 
Ohio, the "Miami Clay Loam," having a definite origin, definite 
physical characters, and definitely adapted to certain crops ; yet 
this soil is locally known in various parts of Ohio as Sugar Tree 
Soil, Clay Upland Soil, Limestone Soil, White Clay Soil, Red 
Clay Soil and Beach Land Soil. In Texas clays are variously 
known as Ashy Flats Soil, Black Waxy Land Soil, Boggy Land 
Soil, Highland Soil, and Tight Soil. Peat, muck and swamp soils 
are often called Acid Soils on account of the humic acid they con- 
contain. No sharp line can be drawn in many cases between al- 
luvial soils and those made by the wind, yet the term Aeolian, or 
Eolian, is convenient when speaking of the origin of many soils, 
but is a misnomer for other soils that are really largely alluvial in 



48 Soils of Califobnia 

origin. The soils of the most productive portions of California 
are soils of the arid region, but are not Arid Soils. This term 
properly used applies to the soils formed where the rainfall is 
small in distinction to soils formed where the rainfall is large, and 
has nothing to do with their fertility, or adaptation to crops. A 
common name in Maryland and elsewhere for any non-productive 
soil is The Barrens, but in Alabama it means only the lands where 
there is scant timber. The character of trees or vegetation grown 
often gives the name as the Beech Land Soil, which applies, how- 
ever, only to clay land in Ohio. Beeszvax and Canebrake soils are 
found in Alabama, while Chocolate Soil comes from South Caro- 
lina. The Blue Grass Soil of Kentucky is famous, but many soils 
that are not from limestone are adapted to this grass. Such names 
as Black Soil, Black Land, Black Prairie may mean the silt loams 
of Illinois and Wisconsin, the loams of Ohio, the clay loams of 
Virginia, or the dark clays of Mississippi or Texas. The black 
jack oak trees give the name Black Jack Soil to clays, clay loams, 
and gravel in the Carolinas ; but in Georgia soils growing the oaks 
as well as the mayhaw are known as Black Gum Soil. The clay 
loams of Michigan are known as Black Walnut Soil, while the clay 
loams of Texas are called Black Post Oak Soil. The use of the 
name Black Ash Soil is even more diverse. Baybush Pocoson, 
or Pocoson, means a swamp land that is not subject to overflow, 
in North Carolina, and Brier Pocoson, or Gallberry Land, is 
named in Maryland for the vegetation without reference to the 
flooding. A famous cotton soil of the South is known as Buck- 
shot Soil because it crushes into grains, or buckshot, when dry. 
In North Carolina they have the black spongy Buckleberry Soil 
of the swamps ; in Louisiana sandy soils named for the Bullnettle 
or Chinquapin. 

A disintegrated rotten limestone combined with abundant 
humus gives the well-known Canebrake Soil of the South. The 
soil resting on bedrock is often called Capsoil, a term that lacks 
the definiteness of the better name — residual soil. The Chalk 
Soils of England and France that originate from, the chalk de- 
posits are well named, but many whitish colored soils receive this 
name that have no chalk in them. The name Cold Soil might 
suggest that the land was retentive of water late in the spring or 
was badly located on the north side of a mountain, but would 
not point out the physical character of the soil as a name should 
do. The crayfish live in soils where they do not have to go deep 



Soil Classification Necessaey 49 

for water; hence we find the name Crawfish Soil in several 
states. Cedar Soil, Chestnut Soil, and Cypress Soil are names 
whose origin is obvious. The name Cumulose Soil was used for 
some time but has given place to other names in late years. It 
was applied to accumulations in situ for years or centuries of 
organic and inorganic material in lakes that had no outlet : to the 
peat, muck, or swamp soils in part at the head of valleys, in 
deserted river beds, in river deltas and other partially drained 
areas. Some soils in South Carolina are called Deadland Soil, not 
because the clay lacks in fertility but because it is sticky and 
hard to cultivate, that is not lively and not to be moved easily. 
In the arid regions of the West, the Dust Soil rises in the air at 
the merest puff of wind. The coarse detrital material caused by 
a flood, such as a cloudburst in the arid regions, is called by 
some Dilluvial Soil. An inappropriate name proposed for sedi- 
mentary soils was Endogenous Soil, as objectionable as the term 
Exogenous Soil which was proposed for transported soils. Fine 
Soil is a term that should be used only with reference to the 
texture of the soil, or as an adjective of praise, but not as a soil 
name. The name Flat IVoods Soil is used for poorly drained 
clays in Mississippi ; while similar similar soils are known in 
West Virginia as First Bottom Land Soil, and as Flat Fine Wood 
Soil in Florida. In the cotton states where the surface of the 
lands has been eroded, exposing the unproductive subsoil, it is 
called Galled Soil. The sands of California, the loams of Illinois, 
and the mucks of the South, are all good Garden Soil. The resi- 
due of coarse swamp grass, sedge, flag, etc., is called Grass Peat 
Soil in some states. A general term for deposits from melting 
ice sheets is Glacial Soil, which is more variable in character than 
alluvial soils and in general is nearly as productive. The glacial 
and boulder clay contain a variety of minerals finely ground and 
intimately mixed, and are very fertile when they contain enough 
sand and gravel to be pervious to water and workable. The 
Glade Lands, or Conowingo Barrens of Maryland are very dif- 
ferent from the Glade Soil or muck of Kentucky. Many soils 
are derived from granitic rocks, but the name Granite Soil is 
not more specific ; it may be a sand, loam, sandy loam, or some- 
thing else. In Alabama some clays are called Gray Land, Gray 
Prairie, or Gray Soil; but these names mean a sandy loam in 
Virginia, a silt loam in South Carolina and Tennessee, a loam in 
Texas, and a sandy loam in Georgia. 



50 Soils of California 

The name Gumbo is well known from the Dakotas to the 
Gulf of Mexico and west to the Pacific. It is not confined to the 
clays but is loosely applied to any tough and very plastic soil that 
is very sticky when wet and hard when dry. The name White 
Gum Slash Soil and Glady Soil are Texan local names. A rough 
sandy loam in Georgia is known as Rough Pimply Soil, and a 
peaty clay in Mississippi is called Heavy Bottom Soil. The name 
Hemlock Soil means a loam in New York and a sand in Michigan. 
The name Hog Walloiv Soil indicates hummocks in California, 
hollows in Texas, and land where the "hog-haw" trees grow in 
Louisiana. Soils which are rich in humus are generally in better 
physical condition than those low in this organic matter, as humus 
is somewhat plastic and tends to hold the soil in a more loose 
condition, but Humus Soil is a misnomer. The micaceous loams 
of Alabama are called Isinglass Soil. The origin of the name 
Ivyland Soil in North Carolina and the Jack Pine Soil in Michi- 
gan are obvious. Soils formed where lakes have dried up are 
geologicallv known as lacustrine or lake soils, but the term Lake 
Front Soil a])plies only to the lands along Lake Erie in Pennsyl- 
vania. The name Laterite (brick earth) is commonly applied to 
any red soil, but its use should be restricted to red, iron-stained, 
residual clay soil formed by the weathering of volcanic rocks. 

Limestone Soil and Limestone Land indicate the origin of 
the soil, which may be any one of several kinds. One term that 
has been so loosely applied as to rob it of its significance both as 
a geologic term and as a soil name is Loess. It is even misused 
as synonymous with adobe. Its origin whether as eolian or sedi- 
mentary,' or both, is still a matter of controversy. Any soil too 
wet to give a solid footing is known as Looseland Soil in Delaware. 
The term Marine Soils is general and applied to soils that consist 
of stratified gravels, sands, silts, and clays deposited originally 
in ofifshore water, and later raised above the sea level, where they 
have not consolidated into rock and weather rapidly. Such 
names as Marly Peat, Medium Peat, Peaty Loam, and Moss Peat, 
can only be used locally. The Mesquite Soil is Nevada is sand, 
and that of the mesquite flats or j)rairies of Texas is a clay loam. 
The moors of Scotland give us the name Moor Earth. A general 
term loosely applied is Mountain Soil. The rocks high up m the 
mountains often consist of granites, gneiss, schists, slates, hme- 
stones. and igneous rocks. These give rise to stony soils, or rough 
broken areas best suited to forestrv, but the soils themselves may 



Soil Classification Necessary 51 

vary from coarse gravels and sands to clays. The Mulatto Soil 
or Mottled Soil of the South takes its name from its yellow color, 
and is wholly different from the Niggerhead (boulders) lands of 
New England. Many varieties of soils contain large amounts of 
lime and are locally known as Marl Soil. Wherever oak trees 
grow the term Oak Soil comes into use. The term Peaty Alkali 
Soil is one that would puzzle most field analysts to identify. The 
Piney Wood Land of Texas is a clay soil; the Pine Barrens of 
Maryland is a sand; the Piney Woods of Alabama a loam; and 
the Pine Flats of Arkansas a clay loam. The Post Oak Flats, 
Post Oak Prairie, and the Post Oak Szvags from Virginia vary 
from heavy clays to sandy loams. Pipeclay Soil is a local name 
used from Maryland to California. Any treeless soil of the 
middle west may be called Prairie Soil without reference to its 
real character. 

The name Redlands means a clay in xA.labama, Virginia and 
Texas; a loam in Missouri; and a sandy loam in Georgia and 
Wyoming. The Red Clay of Delaware is a silt loam technically 
known as the "Norfolk Silt Loam," and the color is generally 
yellow instead of red. In Virginia Red Clay Soil is generally 
synonymous with Mulatto Soil. The dark clayey cotton soil of 
India is known as Regur, a name that has lately been transplanted 
to this country along with the Egyptian cotton. Flooded lands 
along the sea coast are often called Salt Marsh Soils. All kinds 
of soils have been called Scrub Oak Soil. Where soils are com- 
posed of materials that have not been subjected to any appreciable 
transportation they are often called Sedentary Soils, and by some 
are divided into residual soils when they consist of residue left by 
rock decomposition, and cumulose when they result from the 
slow accumulation and decay of plant remains. Some loams in 
Pennsylvania contain fragments of shale of the size and shape of 
shoepegs and the soil is locally known as Slioepeg Soil. The com- 
mon use of the names Silt Soils and Sand Soils means rock pow- 
ders produced by the mechanical pulverization of various min- 
erals, of which quartz is the most common. If the fragments are 
not worn or rounded the sand is said to be sharp. Compare this 
loose use of these names with the precise definition given on 
another page. Any soil that is rich in available plant food is a 
Strong Soil; any tenacious heavy soil is a Stiff Soil. 

The most mischievous and misleading name is Sterile Soil, 
apphed to any soil that does not produce vegetation of some kind 



62 Soils of Califobnia 

naturally, such as the lands of the deserts, sandunes, lavas, etc. 
It is nearly always a misnomer as the sterility is not due to the 
inherent character of the soil, but to local conditions, such as 
climate, lack of irrigating water, etc. In the humid regions many 
soils that are said to be IVonwnt Soil, and sterile, are simply soils 
that are sick, tired, abused or poisoned by toxins, and recover 
all their vigor when restored to proper physical condition. 
Swampy soils may be called locally Tamarack Soil, or for any 
other tree that grows in them, or Tidal Soil if near the coast 
where high tides submerge them. Sandy soils of glacial origin 
are often called Till; while beds of volcanic ash are called Tuff 
or Tuff Soil, but are light soils and never tough soils. Any soils 
that water, ice, or wind have brought from higher levels and 
deposited over lower lands are Transported Soils. Any soil con- 
taining decomposed organic matter in an advanced stage of 
decomposition, making it a rich soil for growing vegetables, may 
be called locally Vegetable Soil, Vegetable Muck, or Vegetable 
Loam. The English name JVacke is applied to a dark compact 
clayey soil resulting from the decomposition in place of basaltic 
rocks. Any dark colored or sandy soil that absorbs and retains 
heat readily is a Warm Soil. Any soil that is easily washed away 
by rains is a Wash Soil. The plastic clays of Virginia and Texas 
are known as Wax Soil or Tallozv Soil. White Oak Soils are 
loam or silt soils in Illinois and Maryland, and clay in Missouri. 
A silt loam in the South is often called White Land Soil. It 
shows a groping towards identification and classification when 
the vernacular contains such terms as Beesivax Soil for sticky 
clay in North Carolina ; Bugle Land Soil where the pitcher plant 
grows in Georgia; Chaffy Soil or sands that the winds blow like 
chaff in Delaware ; Sponty Soil that squirts up water when stepped 
upon in Pennsylvania ; Yelloiv Prairie Soil for the treeless clay 
loams of Alabama ; and Tight Soil tliat is hard to turn over 
with a plow in Texas. 

California has many local soil names which are noted with 
the technical names in the latter part of the book. Thus we have 
Dry Bog Land as a local name for the Portersville clay adobe 
around Portersville; Dry Bog Adobe for the Portersville clay 
loam adobe ; Dry Bog Soil for the Stockton clay loam adobe in 
the Fresno region ; Foothill Soil for the Placentia loam adobe 
around Santa Ana ; and Hogwalloiv Land for the Dunnigan clay 
near Woodland. The Santa Cruz sandy loam is locally known 



Soil Classification Necessary 53 

as Redwood Soil, where the redwoods {sequoia sempervirens) 
grow. The Sacramento clay is known as Tule Land near Marys- 
ville; the Fresno sandy loam of the San Joaquin Valley is often 
called White Ash Land from its color and not for trees ; and the 
same name is given locally to the Fresno fine sandy loam ; the 
Feather silt loam is known as Black Land near Marysville. Wild- 
goose Land is a nickname for the lower, poorly drained alkali 
land, unproductive on account of alkali, occupying spots in the 
Colusa area. The term White Alkali Soil is common for lands 
where the soda salts are largely sulphates, and Black Alkali Soil 
where the soda salts are carbonates. 



PART IV 

CHAPTER VTII 
SOIL PARTICLES 

The soils of California include those of the coast, of the 
coastal and interior mountain ranges, foothills and valleys. The 
soils of certain type areas in each province have been classified 
by the U. S. Bureau of Soils, Washington, D. C, and divided 
into a number of series, varying in field characteristics, topog- 
raphy, origin or mode of formation, and agricultural importance. 
They range from the residual and colluvial soils of the mountain 
sides, foot slopes, and foothills, to deep and extensive flood plains 
and delta sediments, and ancient and modern marine and lacus- 
trine deposits. While some of the series are confined to a single 
coastal or interior mountain range or valley, others are of wider 
range and extend over large areas in various parts of the state. 
The value of these soils and their adaptation to crops is largely 
dependent upon the possibilities of irrigation and upon local con- 
ditions of rainfall and temperature, all of which are to a great 
extent dependent upon the latitude and upon topography. They 
range in agricultural importance from those devoted only to 
extensive grain farming to the most valuable and intensively cul- 
tivated lands devoted to citrus fruits, vines, and special crops 
such as dates, cotton and rice. 

In the present struggle for supremacy in commerce the 
importance of accurate knowledge of agricultural conditions is 
becoming daily more evident. It is important that the men who 
control land and who are responiblc for its future value should 
have at least a fundamental knowledge of the composition of the 
common soils to furnish a foundation of facts upon which to 
build a knowledge of agriculture. A ready working knowledge 
sufficient for everyday use lies at the basis of success in every 
industry and profession. The classification used here is taken 
from the work of the U. S. Bureau of Soils. 

ALL SOILS CONTAIN THE SAME MINERALS. One of 

the most important facts established in recent years is that all 



Soil Particles 55 

the common minerals are distributed through nearly all the soils, 
and that normal soils in the most diverse regions are remarkably 
similar in this respect, all the important soil minerals being pres- 
ent in variable quantities. This fact has revolutionized the study 
of soils and their treatment by the land owner. 
THE NEW THEORY. The theory upon which the United 
States Bureau of Soils works in their classification and correla- 
tion of soils is that practically ALL SOILS contain sufficient 
plant food for good crop yield, and that this supply is indcfinitc'v 
maintained. That the productiveness of a soil depends even 
more upon its PHYSICAL characteristics than on its chemical 
composition. That every soil is intended to grow certain definite 
crops, according to climate and local conditions, and that success 
largely depends upon finding the proper crop for each soil. 
SOIL PARTICLES. The basic material of the soil is an 
aggregation of mineral particles ranging from two millimeters in 
diameter to particles so small that they tax the power of the best 
microscopes. The dififerent sizes of these particles and the dif- 
ferent properties of the different sizes affect the texture, water- 
bearing capacity, aeration, and other properties of the soil. The 
minerals themselves are only slightly soluble, but have in the 
aggregate absorptive capacity in a high degree. This provides a 
dilute nutritive solution, or mineral soup, of sufificient strength for 
the needs of the plants. It is evident therefore that the physical 
analysis of the soils is far more important than the chemical or 
mineralogical analysis. The modern study of the soil is based in 
fact largely upon the physical structure of the soil, and upon the 
soil solution. 

SIZE OF THE SOIL PARTICLES. The study of the physi- 
cal character of the soil begins with the particles that compose 
it. If we consider each particle in a pure soil to be a sphere, 
then the number of particles in a gram of pure soil may be cal- 
culated, the result being as follows : 

Number of Particles 

Fine gravel 2. to 1mm 252 

Coarse sand 1. to 0.5mm 1,72.3 

Medium sand 0.5 to 0.25mm 13,500 

Pine sand 0.25 to 0.1mm 132,600 

Very fine sand 0.1 to 0.05mm 1,678,000 

Silt 0.05 to 0.005mm 65,100,000 

Clay 0.005 to 0.000mm 45,000,000,000 

Since normal soils are a mixture of gravel, medium, fine and very 
fine sands, silt and clay, the number of particles in the soil of 



66 Soils of Califobnia 

a particular class will depend upon the number of particles present 
of the above kinds. The approximate number of soil particles 
present in one gram of soil has been calculated as follows : 

Particles. 

Sandy loam contains 6,485,000,000 

Fine sand loam 6,902,000,000 

Silt loam 9,639,000,000 

Clay loam 16,371,000,000 

Clay 19,525,000,000 

The importance of these millions of particles in any mass of 
soil lies in their relation to the surface area of each particle. 
These grains are not in actual contact but separated from each 
other by thin films of moisture, or in extremely dry soil by actual 
air space. These spaces between the particles will differ in 
size and shape according to the size and shape of the soil grains. 
SURFACE AREA OF THE PARTICLES. The surface of 
the particles holds the moisture, known as film water. The 
greater the surface area of the particle the greater the amount 
of water they hold in the films, or the greater amount of mineral 
soup present for the plant hair rootlets to feed upon. This in- 
creases also the rate of chemical solution, increasing the amount 
of available plant food. A rock three feet cube exposes 54 square 
feet of surface; divided into one-foot cubes, the surface area is 
increased to 162 square feet; if broken into one-inch cubes it 
presents nearly 2000 square feet to erosion and decay; if reduced 
to bits one-twelfth of an inch cube, the square feet of surface is 
increased to about 20,000 square feet, or nearly one-half an 
acre in area. When we remember that in soil analysis in the 
laboratory, the soil particles are actually separated and classified 
into six fractions of a millameter, ranging from 1. to 0.005 in 
diameter, and the percentage of each size obtained, it is evident 
that the necessary information has been gained as to its value 
as a feeding ground for crops. 

The immense area exposed to the hair-like feeding roots of 
plants by soils is shown in the following table which gives the 
internal surface area of field soils in square feet. A cubic 

foot of Square Feet 

Coarse sand contains a surface area of 40,500 

Medium sand 44,500 

Sandy loam 66,600 

Fine sandy loam 68,000 

Silt loam 104,000 

Clay loam 136,500 

Clay 142,000 

That is, the internal surface of the soil particles on a cubic foot 



Soil Particles 57 

of clay represent a film surface of nearly three and a quarter 
acres in area, or in other words one pound of coarse sand would 
have about 400 square feet of surface, to 2000 square feet in 
the case of clay. 

SOIL SPACE. The space between the particles is also of 
great importance in determining the circulation of water in the 
soil and its capacity for retaining capillary water in the right 
proportion for plant growth. This depends upon how the soil 
particles are arranged independent of their size. The physical 
properties of the soil depend upon this more than upon the chem- 
ical composition. The physical properties in turn have a funda- 
mental bearing upon the chemical and biologic properties of the 
soil. The simplest arrangement would be that of spheres touch- 
ing each other ; but such could be arranged in columnar order, 
touching each other at four points, or in oblique order, each 
touching one another at six points. If there are spheres of 
diflferent sizes the small ones would rest in the spaces between 
the larger ones so that the total voids or pore space would be 
greatly reduced. This could be continued until the mass was 
practically solid. Soil particles are, however, irregular in shape 
and uneven in size, giving each soil an individuality in character. 

TEXTURE. The size of the mineral particles determines the 
soil texture, which influences alike the relation of moisture and 
the chemical changes that take place through oxidation, especially 
of the organic bodies in the soil. The texture determines to a 
large extent the relative capacity of the soils to hold water. Under 
equal conditions of depth and exposure coarse grained soils hold 
less moisture and more air than fine grained soils, so that as a 
whole they contain less soil solution, and consequently less nutrient 
material available for the plants. They have generally a lower 
absorptive capacity and permit more rapid oxidation. Another 
important factor is the structure or the arrangement of the min- 
eral matter. In some soils the mineral portions have a granulated 
arrangement of flocculated masses, making the soil loose and 
porous ; in others the grains exist in a compact form, making the 
soil hard and compact. The adobe soils, for example, are hard 
and compact, while sands are open and porous. Another factor 
is the amount of humus or organic matter present, as it influences 
not only the productive capacity of the soil but also its adaptation 
to crops. The following table illustrates the effect of texture : 



58 Soils of California 

Coarse sand containing- 4.8% of clay holds l.G'/o capillary moisture 

Medium sandy loam " 7.3% " " 7.0% 

Fine sandy loam " 12.6% " " 11.8% 

Silt ■■ 10.6% '• " 12.9% 

Silt loam ■• 17.7% " " 26.9% 

Clay loam " 26.6% " " 32.4% 

Clay •■ 59.8% " " 46.5% 

POROSITY, There is always some unoccupied or pore space 
or voids among the particles in all soils. If the particles are fine 
the voids are small. If the particles are large the pore spaces are 
large. A clay has more total pore space than sand, although 
the individual spaces are much smaller in the clay. This rela- 
tion between texture and pore space is shown by the following 
table : 

Percent Pore Space 
by Volume 

Clean sand contains 33.50 

Coarse sand 40.00 

Medium sand 41.80 

Fine sand 44.10 

Sandy loam 51.00 

Fine sandy loam 50.00 

Silt loam 53.00 

Clay 54.00 

Adobe 56.00 

A porous soil i)ermits a freer circulation of the gases. The 
porosity of a soil depends upon (1) the state of divisibility. (2) 
upon the natural arrangement of tlie particles, and (3) upon the 
voids, their size and arrangement. 

SOLUBILITY OF THE SOIL MINERALS. The common 
soil minerals mentioned in Part I are very slightly soluble, about 
as much so as ordinary glass ; but in the finely divided state in 
which they exist in the soil, an enormous surface is presenteii 
upon which the film waters act, forming a soil solution which 
contains the necessary amount of the mineral plant food ele- 
ments. Twenty-five parts of potash and ten parts of phosphoric 
acid per million of solution is ample for the needs of the plants ; 
and the soil solution is said to be saturated when it contains 
these amounts. 

The degree of solubility of each mineral in the water in con- 
nection with the mixture of so many kinds of minerals as are 
found in the soils makes the concentration and composition of the 
soil solution nearly the same for all soils. With 1,000,000 pounds 
of water in contact with 5.000.000 pounds of soil the solution will 
contain 25 pounds of dissolved potash, although the amount of 
potash in the soil may vary from 30,000 pounds in one soil to 



Soil Particles 59 

120,000 in another. As the 25 pounds of potash is gradually 
removed from the film water by plants, more goes into solution, 
so that no sensible change in concentration takes place in the film 
water solution. 

THE SOIL SOLUTION. The water in the soil absorbs 
gases and takes up soluble mineral, animal, and vegetable matter 
from the heterogenous mixture called the soil. The component 
parts of the soil consist of mineral debris from rock decomposi- 
tion, organic matter from the fermentation and decomposition 
of former animal and plant tissue, carbon dioxide and other gases 
from the air. and the products of the activities of myriads of bac- 
teria, fungi, and enzymes. It is from this complex solution that 
the plants, through their hair roots, draw all the material from 
the soil that is involved in their growth, except that absorbed from 
the atmosphere. It is well to remember here that after all only 
about ten per cent of any vegetable growth comes from the soil 
and that the remaining ninety per cent comes from the atmos- 
phere. Burn a dried plant and the ash or mineral portion is 
largely from the soil ; the carbon, hydrogen and oxygen that made 
up the bulk of the plant came from the atmosphere. The study 
of the soil solution and its relation to the soil and to plant growth 
is of the highest importance, but belongs to agricultural chemistry 
and to biology and not to the origin and classification of the soils. 
So far as the mineral portion of the soil is concerned the concen- 
tration of the minerals dissolved in the soil solution under normal 
conditions is sufficient to support ordinary plant crops. Changes 
in the concentration and proportion of the minerals dissolved 
produce a rapid or a slower growth, and a greater or less total 
growth, and dififerences in the character of the growth, such as 
the tops growing faster than the roots, or the reverse. The soil 
solution affects the physical character of the soil, for most dis- 
solved substances affect the granulation or flocculation of the soil 
particles. Magnesium, sodium and potassium chlorides and 
sodium nitrate make the soil moist in dry weather by increasing 
the surface tension of the soil solution. When this tension is in- 
creased, water is drawn towards this point ; hence fertilizers may 
assist in drawing water up in the soil. Oily substances do not go 
into solution but spread in a film decreasing the surface tension 
and diminishing capillarity. Some organic matters in solution 
act the same as oil. 



60 Soils of Caxifobnia 

PHYSICAL ABSORPTION, OR ADSORPTION. Soil par- 
ticles attract and hold materials such as gases and dissolved salts 
upon their surfaces. This is called absorption or adsorption and 
is not to be confounded with chemical absorption. It varies with 
the extent of surface exposed, and is greater in the fine textured 
soils. This is an important factor in the retention of fertilizers. 
This important property of the soils also tends to control the con- 
centration of the soil solution and to prevent undue waste of 
material. This adsorptive power varies greatly in different soils 
and with different minerals, and varies for different substances 
and parts of substances ; thus it is stronger for potash than it is 
for chlorine, and will absorb potash from chloride of potash. Tt 
is an important factor in regulating the concentration of the soil 
solution. This action also purifies the waters passing through the 
soil. If it were not for this property, wells would soon become 
unwholesome from seepage. Soils absorb the gaseous products 
of dead bodies and the products of the decomposition of animal 
and vegetable matter. They withdraw and retain certain minerals 
held in solution, as the sands along the seashore absorb the saline 
matter so that quite pure water may be obtained by digging in the 
sand some distance back from the water's edge. Soils absorb the 
soluble minerals from fertilizers. If a soluble sulphate, chloride, 
or nitrate of an alkali comes in contact with soil a part of the base 
and none of the acid is withdrawn. Generally, however, there is 
some other base in the soil that may join the liberated acid form- 
ing new products, otherwise the acid leaches out. Soils also 
absorb dissolved substances by mechanical inclusion or trapping 
(imbibation) as a sponge; or a mineral such as Hme or ferric 
oxide may absorb phosphoric acid, forming a new compound, as 
lime or iron phosphate. Soils absorb potassium more readily 
than sodium, magnesia than lime, and ammonia more than any 
of these bases. More potassium is absorbed from the sulphate 
than from the chloride of potassium. Clays especially absorb 
potassium. Oxides of iron absorb potassium and ammonia. Soils 
remove both the base and acids of soluble phosphates and silicates. 
The nitrogen of insoluble organic bodies which nitrify slowly is 
absorbed and retained ; but nitrate of soda is an exception and is 
not absorbed, and is readily washed out of the soil. The absorp- 
tive power depends upon the relative amounts of surface exposed 
which depends upon the size of the particles, upon the kind of 
surface acting, upon the concentration of the solutions, upon the 



Soil Particles 61 

time of contact, and upon the temperature. The finer the par- 
ticles the greater the surface and the greater the absorptive 
power. The fine soils thus hold the plant food too closely to allow 
rapid loss through drainage. Heavy soils containing hydrated 
ferric oxide absorb bases more readily than the light soils. Soils 
rich in humus are better absorbers than soils not so rich. The 
absorptive power of soils is many times greater than it is ever 
called upon to exert in sustaining field crops, or in fixing applied 
fertilizers. An acre of soil nine inches deep could absorb nine 
and a quarter tons of phosphoric acid, while 500 pounds is the 
maximum for field crops. A soil can absorb twenty-seven times 
as much potash as is called for, and thirty-two times as much 
ammonia. During dry weather plants require a soil that is ab- 
sorptive and retentive of water. The water absorbed by the roots 
passes into plant circulation and must be evaporated by the leaves. 

Pounds of 
water 

1 acre of wheat exhales 409,832 

Clover 1,096,234 

Sunflowers 12,585,994 

Cabbage 5,049,194 

Grape vines 730,733 

Hops 4,445,021 

Cultivation conserves the soil moisture. 



CHAPTER IX 
SOIL MOISTURE 

Soils var)- widely in their moisture contents. The supply is 
determined by precipitation as rain or snow, by underground 
seepage, and by irrigation. The soil moisture with its dissolved 
substances forms the nutrient solution for the support of plants ; 
yet water may exist in soils and not be available for nutrition. 
Soils may contain water in different ways or conditions, each con- 
dition exhibiting markedly different physical properties and pecu- 
liarities. The water present may be (1) gravitational water, (2) 
capillary water. (3) hygroscopic water, (4) chemically combined 
water or water of hydration, and (5) as film water. 
GRAVITATIONAL WATER. This is water that is free to 
move through the soil under tlie influence of gravity. It is water 
present in excess of the amount which the soil is able to retain 
and which is free to drain away, and depends upon the maximum 
capacity of the soil to hold water. This retentive capacity of the 
soil varies according to the physical properties. Plants suffer 
much more quickly from drought on sand where the retentive 
capacity is small, than on clay where the retentive capacity is 
large, even when the soils are equally wet at the outset. The 
drainage features of the soil control the amount of gravitational 
water retained ; the amount of excess salts held in solution ; and 
often materially influence the organic constituents, the aeration, 
and the oxidation of the soil. Artificial drainage gives greater 
depth to the working soil, warms the soil, admits air, increases 
the amount of plant food, lengthens the growing season, improves 
the texture, increases the porosity, and prevents waste through 
heavy washing. 

CAPILLARY WATER is that which is retained in the capil- 
lary spaces in spite of gravity, and which is capable of movement 
under capillary conditions. The capillary capacity of a soil de- 
I)ends upon (1) the texture of the soil, (2) upon the structure, 
(3) and upon the organic content. The capillary water is the 
principle source of water and mineral plant food to the plants, 
and is probably the seat of important chemical and biologic 



Soil Moisture 63 

changes in the soil. The relative amount of capillary water de- 
pends upon the texture, the depth of the soil, drainage, and the 
amount of organic matter present. The best amounts of capil- 
lary water, called the optimum amount, varies with each soil, 
ranging from twenty per cent of the weight of dry clay soil to 
four per cent for some sandy soils. 

Capillary movement may take place upward, downward or 
laterally. After a rain, when the surface of the soil is more 
moist than that below, capillary action aids gravity and hastens 
the penetration of the water downward, but as soon as the surface 
soil becomes the dryer the capillary flow is upward. Where plants 
are growing the movement is towards the roots from all sides 
where the soil has more water than in the vicinity of the roots. 
The rate of the capillary movement varies with the distance the 
water must be moved and the character of the pore spaces through 
which the water must move. For fine sands the rate by experi- 
ment was 2.37 pounds per square foot per day of 24 hours, and 
for clay loam was 2.05 pounds. When the soil becomes nearly 
air dry to any considerable depth the pore space becomes filled 
with air and this must be expelled before water can enter. In 
some sandy soils the air spaces are large, the air readily dis- 
placed, and the soil easily moistened. In fine soils a moderate 
shower fills up the surface pores at once and prevents the escape 
of the soil air, and this prevents the entrance of the water to any 
depth. Clays especially remain dry below even when the surface 
is eroded by heavy rains or irrigation. On such soils time must 
be taken to let the water soak in slowly, gradually displacing the 
air from the fine pores of the soil. 

WATER VAPOR. Even when the soil contains neither 
gravitational or capillary water the air that fills the pores or voids 
contains water vapor that is important in plant nourishment. 

HYGROSCOPIC WATER, or moisture, is that which con- 
denses from the air on the surface of the soil particles when the 
soil is allowed to become air-dry. It is found on the surface of 
the grains and is not capable of movement by gravity or capillar- 
ity. The hygroscopic moisture adheres to an air-dried soil and 
undoubtedly plays an important part in the chemical changes 
which take place. Under ordinary climatic conditions loams and 
clays contain as much as four to eight per cent of their weight 



64 Soils of Califobnia 

of hygroscopic moisture, and soils rich in organic matter contain 
even more. 

Sands have Httle power of retaining water and all added 
water flows at once to lower levels and the amount held by 
capillarity is far less than in soils composed of finer materials 
such as silt and clay, but they can retain considerable hygroscopic 
moisture. 

WATER OF HYDRATION. This is the water chemically 
combined with the minerals and is of little use directly to the 
plants in humid climates ; but in arid climates certain desert plants 
avail themselves of water from this source, dehydrating the mate- 
rials. This water is also known as the zvater of crystallisation. 
Thus, gypsum is sulphate of lime (CaS04) plus (2H2O) two 
molecules of water; or in other words, 100 pounds of common 
land plaster or gypsum is really 79.1 pounds of sulphate of lime 
and 20.9 pounds of water. When the gypsum is burned the water 
of crystalHzation is driven off and "plaster of paris" is left. Other 
minerals contain water of crystallization, as glauber salts (sul- 
phate of soda), borax, etc. 

FILM WATER. This is the most important form in which 
water exists in soils, yet little attention has been given it until 
recently. Drop a marble into mercury and it comes out dry. Lift 
it from water and it carries a film of water over its entire surface 
due to the attraction of the marble for water, or adhesion. The 
film is thick on account of the attraction of the particles of water 
for each other, or cohesion. 

Soils must be moist or plants will not grow, but this water 
does not fill the spaces in the soil proper ; it sticks to the grains 
covering them with a thin film while the air fills the spaces be- 
tween the particles. It clings so closely that it cannot be rubbed 
off and is not easily driven off except by heats greater than that 
to which soils are naturally subjected. 

The very driest road dust has some film water clinging to it. 
It is the film water that is the feeding ground of the plants, the 
mineral soup that nourishes them. The hair-like rootlets, some 
of them only three-hundredths of an inch in diameter, must come 
into intimate contact with the film of moisture, without being 
excluded from the air supply which promotes their growth. The 
right amount of film moisture and air in the air spaces is the key 
to success in modern agriculture. The chemistry and physics of 



Soil Moisture 65 

the film moisture is one of the most interesting studies in agricul- 
tural chemistry. The Bureau of Soils has discovered that there 
is a pressure on the surface of a mineral particle moistened with 
water, acting at an inconceivably small distance from the solid 
surface, which is estimated as at least 10,000 atmospheres, or 
150,000 pounds per square inch, or fifteen times the muzzle pres- 
sure of a 12-inch gun. Under this pressure the concentration of 
the solution is enormously increased in the surface film on the soil 
particle, and chemical changes and reactions may take place there 
which are impossible to duplicate in the chemist's laboratory. 
Each root is at first a slender thread-Hke object which extends 
itself through the voids in the soil. When it obtains lodgment on 
a particle it rapidly increases in size and vigor. From a slender 
fiber of microscopic size, less than the 1/300 of an inch in 
diameter, it may increase to a foot or more across. These root- 
lets spread like an octopus through the soil, feeding on the film 
waters and soil solution. They are always moving, absorbing and 
excreting water and dissolved substances, and ever pushing for- 
ward. When they die they contribute their organic matter to the 
soil and their decay leaves channels through the soil facilitating 
drainage and aeration. 

CRITICAL MOISTURE CONTENT. The amount of water 
available at which the plants are just able to survive is termed 
the minimum or critical moisture content; the highest per cent at 
which the plant will survive is the maximum moisture content; 
and the intermediate point at which any crop makes its best 
growth is the optimum moisture content. Each of these points, 
or moisture conditions, is very definite for each soil and each 
crop. The maximum and minimum points are marked by distinct 
changes in (1) the cohesion of the soil, (2) in the volume weight 
of the soil, and (3) in the freedom with which the soil gives up 
its moisture. Between the maximum and minimum the soil 
works the best; it does not puddle, gives the desired granulation, 
known as good tilth, and the clods are not hard, and the ground 
is easily pulverized. 

The maximum water capacity is the total amount of water 
which can be put into a given volume of soil. It depends upon 
the total pore space of the soil. The following shows the amount 
of water present in some soils at the saturation point : 



66 Soils of California 

Percent at 
Saturation 

Dunesand 40.5 

Coarse sand 39.5 

Fine sandy loam 38.0 

Light silt loam 38.0 

Clay 54.5 

Humus 333.3 

A saturated condition of the soil is unfavorable to agriculture, 
except to the swamp types such as rice and cranberries. The 
gravitational water must be removed by natural or artificial drain- 
age for other crops to grow, as its presence in the root zone is 
injurious to most farm crops. 

EVAPORATION. The sun is the greatest of all pumps, and 
the rate of evaporation for any soil is important. It is relatively 
rapid above the optimum amount of moisture, and very much 
slower below that point, and to a large extent takes place within 
the soil instead of from the surface, the vapor coming out 
through the slow process of diffusion. A dry surface mulch con- 
serves the moisture below by protecting from surface evapora- 
tion, as the capillary movement of water in the dry mulch is 
exceedingly slow. The waters in the lower layers can loose only 
by being raised to the surface by capillary action. This is the 
fundamental secret of dry farming. Evaporation is affected also 
by the attitude of the soil, being greater where the soil is exposed 
to the direct heat of the sun, and less in shaded places. 

WATER TABLE. The point at which water stands in soil 
is called the zvater table. If it is only two or three feet from 
the surface there is not enough dry soil for the roots to grow 
in and they drown. Such soils are said to be shallow. If it is 
too deep, water does not rise from it by capillary attraction and 
the plants suffer from drought. The height of the water table 
depends upon the texture of the soil, the character of the sub- 
soil, the presence or absence of hardpan, natural or artificial 
drainage, etc. If a well is sunk eighty feet and fills up with 
water to within fifteen feet of the surface, it means that the 
ground is full of water to that level. This level is known as the 
ground zvater level, ground zvater surface, or zvater table. During 
wet weather the water table rises, and in periods of drought it 
sinks. In lakes, marshes and streams the water table stands at 
the surface. It is never at rest, rising or falling and moving in 
slow currents through porous rocks and rapidly in joints and 
cracks and underground channels. It is the source of springs, 



Soil Moisture 67 

and is important in extending the process of weathering and rock 
decay below the subsoil and deep into the bedrock. A fluctuating 
water table permits roots to develop during one season at a certain 
depth, and then by a rise or fall of the ground water either 
drowns them or leaves them thirsty. The condition of the water 
level should always be studied in connection with all soils before 
planting anything, and the method of irrigating and the amount 
of water used should be regulated accordingly. In one part of 
this state v/hen irrigation began, the water table was from seventy 
to one hundred and fifty feet down; now it is from ten feet to 
surface level. This shows great waste of water in some manner. 
All water that passes below the depth of root penetration is not 
only lost to all good at the point applied but may be a serious 
menace to land lying lower. Why waste water by soaking the 
ground when the plants feed upon all moisture except gravita- 
tional water? 

The ideal way would be to copy nature and irrigate with a 
spray falling like rain, giving the ground only what it needs for 
film and capillary water and leaving the needed amount of air in 
the voids, and protecting the water from evaporation by keeping 
the surface in good tilth by cultivation, or by mulching. When 
this is done, then the irrigation waters of the state will be con- 
served and extended to several times the amount of land they 
are now used for. 



CHAPTER X 
VARIOUS DEFINITIONS 

Soils become sticky or plastic, when mixed with water, and 
this property is termed plasticity. In general, the finer the soil 
the greater the plasticity, as in the finer textured clays. Sandy 
soils possess it to some extent, however, for this material adheres 
when wet but falls apart on drying, while clay soils become hard 
on drying. The plasticity of a soil afifects its cultivation and 
drainage. 

Some soils expand on wetting and shrink on drying. This 
is called checking. In a clay soil the surface film draws closer 
about the particles as the water dries out, and moves the particles 
closer together. As the mass does not move as a whole, cracks 
or checks are developed. Very pure clay when dried contracts 
18.3 per cent of its original volume, sandy clay 6 per cent, and 
muck 20 per cent. The finer the texture the greater the shrinkage. 
When large checks or cracks are formed, the roots of plants 
may be broken, or at least injured, the soil dries out to greater 
depths than from surface evaporation, and the advance of root- 
lets is interfered wnth. 

Small particles of soil, according to the moisture conditions, 
may adhere to a large one, or a number of small particles may 
adhere toegther in a group. This structure is called granular, 
or crumb structure, when the aggregate of particles is not large 
and readily fall apart. When the group reaches a large size and 
interferes with cultivation they are called clods. 

Dissolved salts, such as lime, oxides of iron, and silica, may 
be drawn to the surface when the soil is moist, and on drying may 
bind or cement the surfaces together, making the fully dried soil 
much harder than when moist. Some of the red soils of the 
coastal plains show a tendency to case harden at the surface, an 
action due to the iron compound present. See hard pan, described 
elsewhere. 

SOIL ATMOSPHERE. Plants must have air to breathe and 
need a well- ventilated soil as a rule. The oxygen of the atmos- 
phere penetrates to a great depth, and acts especially upon tlie 



Various Definitions 69 

lower oxides of iron, converting them into peroxides and pro- 
moting decay. The soil atmosphere contains less oxygen and is 
considerably richer in carbonic dioxide and nitrogen than the air 
above the surface. The diffusion of air through soil is slow, and 
cultivation is necessary with most crops in order to secure more 
perfect aeration. Unless air freely enters the soil and is fre- 
quently changed, or, in other words, unless the soil is well ven- 
tilated, nitrification cannot go on. Hence the necessity for plow- 
ing, spading, raking, and stirring the soil by the various methods 
of cultivation. The air drawn into the soil aids the roots in as- 
similating plant food. Few vegetables or trees tolerate having 
their roots permanently bathed in water during the growing sea- 
son, any more than a human being can keep well if his shoes 
and stockings are constantly wet. A few species of trees like 
the bald cypress {Taxodium disfichnm) accommodate themselves 
to permanently wet earth by processes from their roots which 
bring air to them ; but this is living like a diver, who is dependent 
upon the air tube that connects him with the necessary atmosphere 
above. 

Gravity, cohesion, and other forces tend to bring the soil 
j)articles too close together, giving the soil a compactness that is 
undesirable. Water and air will not penetrate a soil that is 
packed too close. When a soil is plowed, air is brought into 
direct contact with particles that had been previously shut away 
from it. Plowing and other methods of cultivation are chiefly 
beneficial because of their effect upon soil ventilation. Heavy 
soils need more cultivation and more thorough cultivation than 
light soils. The purpose of cultivation is to break up and fine 
the soil more than it is to keep down the weeds ; to admit air into 
the soil and to form mulches to check the evaporation of the 
capillary and film waters. 

The aeration of the soil and the structure and arrangement 
of the particles is improved by alternating deep rooted and shal- 
low rooted crops, just as it is improved by alternating deep 
plowing with shallow ploughing. 

SOIL TEMPERATURE. Soils must be warm in order to 
produce crops. The colder the soil the slower the seeds ger- 
minate. Crops differ in this respect, for the temperature favor- 
able for the germination of barley is 70 degrees F., clover 7? 
to 100, pumpkins and tomatoes 100. Onions, barley, turnips, 



70 Soils of California 

parsnips, peas, and potatoes are cool plants and can be planted 
when the ground is cold ; tomatoes, melons, squashes, etc., are 
hot plants that do not grow until the soil is thoroughly warm. 

The sun is the furnace that heats the soil, and this heat is 
subject to seasonal and hourly variation. The temperature of the 
soil depends upon (1) the heat supply, (2) upon the specific 
gravity of the soil, (3) upon the specific heat of the soil, (4) 
upon the color, (5) upon the attitude or location, as on a north 
or south slope. (6) upon the conductivity of the soil particles, 
(7) upon the circulation of the air in the soil, and (8) upon the 
character of the water content. The specific gravity of the soil 
afifects the temperature, for the larger the mass is in relation 
to weight, the more heat required to change its temperature ; the 
more dense the soil, the more heat is absorbed by each layer, and 
the more rapidly the heat is conducted through the mass. The 
conductivity of the soil for heat depends upon ( 1 ) composition, 
(2) texture, (3) structure, and (4) moisture content. The 
coarser the structure the greater the conductivity. A compact 
soil conducts heat more rapidly than a loose one and gives it off 
more readily. The coarser the soil the warmer it gets and the 
better it holds the heat ; hence gravelly and sandy loams are 
among the earliest and warmest of soils. A clay, however, warms 
faster than sand, for the particles lie closer together and the heat 
passes more readily from particle to particle, and a clay soil 
loses heat faster than a sand for the same reason. A clay soil 
holds more water and loses more heat through the larger evapora- 
tion ; hence sandy soils are warm and clay soils are cold. Drain- 
ing a soil warms it. Dark soils absorb more heat and are VN-armer 
and earlier than a light colored soil. Uneven and ridged soil 
loses more heat than a smooth level soil. The presence of small 
stones and pebbles make a soil more porous and warmer; hence 
gravelly and sandy soils are the warmest and earliest soils. Clay 
warms faster than sand, but it also loses heat faster. A smooth 
surface absorbs heat more than a rough or rigid one. The "lay 
of the land" or attitude of the soil has an important influence 
upon temperature. A northern slope that receives only one 
third of the sunshine that the same kind of soil receives on a 
southern slope may be seven to ten degrees cooler in summer than 
the soil of the southern slope, while the soil with the southern 
attitude may be from three to five degrees warmer than the same 



Vabious Definitions 71 

soil on the level land lower down, the rays of sunshine striking \l 
at right angles while they strike the level land obliquely. 

Chemical changes in the soil are hastened by a high temper- 
ature and retarded by a low temperature. For example, barn 
fertilizers lie dormant in the soil through fall and winter and 
become active under the heat and moisture of the spring. A 
lumpy soil is cold either because of the lack of humus, or 
through excessive moisture, and its available feeding ground is 
also greatly reduced. Frozen soil means a complete suspension 
of chemical and vital action but not of mechanical. Everyone 
has noticed the "heaving effect" of ice, how fence posts are 
raised, and stones are lifted by frozen ground through the ex- 
pansion of water when it freezes. Soils are pulverized, broken, 
heaved, and improved by freezing. It aids in the decay of the 
mineral matter and fines the soil. 

ELECTRICITY. Weak currents of electricity are effective 
in plant growth, and are being utilized in intensive cultivation. 
They stimulate in some cases the activity of bacteria, and pro- 
mote chemical activity in the soil solution. It is not yet known 
what effect they have upon the physical condition of the soil. 

DESCRIPTIVE TERMS. Common descriptive terms are 
applied to soils to designate certain definite properties. When 
one speaks of a soil as fine, coarse, cold, warm, light, or heavy, 
he should use these words with precision, and as having relation 
to definite properties of the soil, and not use them carelessly or 
loosely. 

Other things being equal, the finer the particles of the soil 
the richer it is, because it contains more internal surface for the 
roots to feed upon, as the film water upon the outside of these 
fine soil grains is their feeding ground. The absolute weight of 
a soil depends upon its absolute specific gravity and the volume 
of pore spaces in the mass. The average specific gravity of soil 
material is 2.65. The following table shows the comparative 
absolute weights of some soils: 

Specific Weight per cubic foot Weight per 

Gravit. Kilos. Pounds acre foot 

Coarse sand 1.60 45.5 100.0 4,356,000 

Medium sand 1.54 43.5 96.0 4,200,000 

Fine sand 1.48 42.0 93.0 4,080,000 

Sandy loam 1.30 36.8 81.0 3,550,000 

Fine sandy loam 1.32 37.4 82.5 3,590,000 

Silt loam 1.24 35.2 77.5 3,400,000 

Clay 1.17 33.1 72.6 3.180.000 



72 Soils of California 

It is seen that the finer the soil the hghter its absolute weight. 
Clay soils may range from 60 to 90 pounds in absolute weight, 
according to their fineness and state of granuation, while sand 
soils may weigh from 90 to 110 pounds per cubic foot. The terms 
light soil and heavy soil as used in agriculture have absolutely 
no reference at all to the actual or absolute weight of the soil, 
but solely to the amount of force required in tilling the land. Thus 
a sandy soil is light because it is easy to cultivate, as the particles 
move easily. Clays are heavy because the particles stick together, 
and the plow and other tools drag heavily. 

The most obvious physical properties of a soil are its tex- 
ture and color, both of whicii indicate important differences that 
influence crops. The texture is determined by the proportion oi 
the different sized mineral particles it contains. This proportion 
is ascertained by actual physical analysis and is the basis of soil 
classification. The soil is washed in water in appropriate ma- 
chinery and the fine and coarser materials separated by centri- 
fugal machines. Some of the coarser particles may be separated 
by sieves. In this way the soil is separated into fine gravel, coarse 
sand, medium sand, fine sand, very fine sand, silt, and clay, and 
the percentages of each present in the soil determine its texture. 
A high per cent of gravel and coarse sand give a coarse texture, 
as a high per cent of very fine sand, silt or clay will give a fine tex- 
ture. 

COLOR. There is no longer any doubt but that the color of 
a soil is important. It indicates some associated properties, caus- 
ing the color, which influences the yield and quality of the crop. 
What the colors of the California soils indicate is brought out in 
the individual descriptions of the soils in Part 4. Just why the 
color should indicate certain qualities is not always apparent. The 
color of a soil is not. as a rule, the color of the individual par- 
ticles, but of material which adheres to the particles. Iron com- 
pounds give rise to red, yellow, blue and gray colors ; organic 
matter to blacks and browns, and their combination with iron salts 
give various intermediate tints and shades. 

In the boulder clays of glacial regions, a bluish color is com- 
mon, due to the presence of protoxide of iron (FeO) resulting 
from a deficiency of oxygen. Where this comes in contact with 
carbonated waters, carbonate of iron is formed and the soil is 
gray ; where there is an abundance of oxygen the iron becomes 



Various Definitions 73 

the sesquioxide (FcaOg) or "iron rust," which has a deep red 
color. Iron quartz sands and residual shale soils have colors due 
to the color of the mass of the particles themselves. 

A dark colored soil absorbs heat much more rapidly than does 
a light colored one, and therefore warms up faster. A dark col- 
ored soil is generally regarded as a fertile soil. Where this is 
due to the presence of organic matter this is true, but it is not 
always a reliable guide, as other properties of the soil must be 
taken into consideration, such as the climate, altitude, composi- 
tion, etc. The color of a soil is a valuable guide to the person 
experienced in the climatic conditions of the given region, as it 
points out the condition and productiveness of the soil ; but one 
versed in productiveness as related to color in the humid regions 
of the east is all at sea when he first looks at the soils of the arid 
and semi-arid regions of the west. A mottled and uneven color 
may indicate poor aeration which is due to poor drainage. "Rich 
black soils" have been favorites in the humid regions from the 
dawn of history, while brownish soils on low ground were be- 
lieved to indicate acid humus or sour lands ; but in the forest such 
colors would indicate decayed wood. Black soils on the upland 
prairies of the east often indicate a full supply of lime carbonate 
and a highly productive soil. Some red soils of the southwest 
are called "mahogany soils" and are considered prizes, but red 
soils produced from iron bearing sandstones are often very poor 
soils whether found in the foothills of the Sierras or in the cot- 
ton states of the south. 

A red soil is apt to be well drained, for the iron rust, or fer- 
ric hydrate, cannot exist in badly drained soils. White soils with- 
in the tracts of red lands may show a watery maceration that is 
injurious. Ferric hydrate has a high power of absorbing gases 
from the atmosphere, standing next to humus in this respect, 
while like humus it renders heavy clay soils more readily tilled. 
The red tint absorbs heat readily, giving a warmer soil, appreciat- 
ed by orchards and vineyards. Yellow soils owe their tint to 
the smaller amount of ferric hydrate and share to less degree in 
its advantages. White soils and light gray soils are regarded with 
disfavor in the humid regions as meaning a scarcity of both humus 
and ferric hydrate through the action of stagnant water, and in 
some localities they are known as "crawfish soils," as they are 
often inhabited by crawfish, whose holes reach water in a short 
distance. 



74 Soils of California 

In the west and in arid regions generally, white and light 
gray tints are very common characteristics of the very best soils. 
They are rich in plant foods ready for use and not affected yet 
by water. This does not refer to the white alkali spots which 
are described under the head of alkali elsewhere. 

SOIL ODORS. When soil has been recently wet it emits a 
peculiar odor which is not disagreeable. This odor comes from 
a neutral organic compound of what the chemist calls the aromatic 
family. The odor is generally penetrating, almost piquant, and 
analagous to the camphorated bodies. It amounts only to a few 
millionths of a per cent and is of little value in most cases in de- 
termining the crop value of a soil. 

FERTILITY. The fertility of the soil was for many decades 
believed to be dependent mainly upon its chemical composition as 
tabulated in the old form of chemical analysis, and older works 
are filled with tables of chemical analysis that are now known to 
be worthless. 

In spite of the tonnage of books on the subject of fertilizers, 
and fertility, the actual knowledge of fertilizers is still very 
meager and almost entirely empirical. The chemical analysis of 
a soil still fails to explain its relative productivity. Chemical 
analysis still fails to determine the amount of fertilizers needed 
by lands. 

Mineral fertilizers have however a decided influence upon 
the physical character of the soil, which is really of greater im- 
portance than its character as given by chemical analysis. Fer- 
tilizers readily affect the granulation of the soils, and all the prop- 
erties dependent upon that, often correct acidity, increase the per- 
meability of the soil and stimulate diffusion. They furnish heat 
that may stimulate the dormant spores of some bacteria into life 
and activity. Fertilizers must be finely (Hvided and used on well 
aerated soil. The phosphates that are insoluble in water are 
slowly dissolved by the acid sap of the root hairs, but largely re- 
main inert. Bones decompose in clay soil so slowly as to be of 
little value. Organic fertilizers such as oil cake, bones, and farm- 
yard, yield only a small portion of their nitrogen during the 
first year. 

The old soil analysis made by extracting the soluble por- 
tions with acid and giving the results as soluble and insoluble 
are now known to be worthless and to mean nothing. A soil 



Okganic Matter ix Soil 75 

which is utterly barren under certain conditions of cHmate or 
moisture may under changed conditions — not changed composition 
— become fruitful in the extreme. All of the citrus regions of 
California are an illustration of this fact. It has been repeatedly 
demonstrated in this state, where dreary stretches of aridity given 
over to sand, sage brush and clay, have been converted into the 
richest of orange groves and vineyards. 

If the arrangement of the soil particles is favorable to root 
action and conservation of moisture, the soil may be made fertile 
by proper water, and by proper treatment, and is therefore 
adapted to certain crops. A soil containing too large a propor- 
tion of iine clay may have too large a proportion of moisture so 
as to be unsuited to cultivation when saturated and become 
equally unfit by induration when dry, calling for the admixture 
of sands to give it a loamy character. A light, porous soil may 
be fertile when watered, but parts with its moisture so readily 
as to be barren if subjected to drought, and is benefited by the 
admixture of some heavier soil. The capacity of a soil to care 
for the water it receives is the most important of its properties. 
The fertility of the soil is largely influenced by the cultivation it 
has received, and by the toxins left by the previous cropping, as 
all crops leave the soil in a more or less unsanitary condition. 
"Snow is the poor man's fertilizer," because it heaves, breaks up, 
loosens, and otherwise changes the physical condition of the soil. 



CHAPTER XI 
ORGANIC MATTER IN SOIL 

Almost every soil contains plant remains. Forest soil con- 
tains decayed leaves and stems, sod land is filled with fine roots, 
and low swampy areas are full of dark organic material. The 
organic material of soil consists in general of the tissue remains 
of plants and to a less extent of animals, numerous products 
of bacterial origin, secretions of algae, fungi, etc., etc. Plants 
are the chief source of the organic matter, the material going to 
decay through the action of bacteria and fungi in addition to the 
purely chemical changes. The chemical composition of the or- 
ganic matter is as variable as the materials from wihch it is de- 
rived and the conditions under which it is formed. Many of 
these are acid, some act as bases (as ammonia and marsh gas). 
They react with each other in many ways, but more especially 
they react with the mineral elements of the soil, forming plant 
foods, and releasing food elements from the mineral combinations. 
Nitrogen, which is not a constituent of the rocks, is made avail- 
able through this organic decay. The percentage of nitrogen 
varies greatly, some humid soils containing less than two per cent, 
while some soils of the arid regions contain over twenty-two 
per cent. Under cultivation the nitrogen in the organic matter 
is changed to forms available to plants. The organic substances 
are greater in the soil than in the subsoil, decreasing with depth. 
Arid soils generally contain less organic matter than the soils of 
humid regions, and the soils of cold climates contain more than 
those of the warm climates. Wet soil contains more than dry 
ones, and clay soils more than sandy ones. Vegetable matter 
after life is extinguished undergoes complete decay which returns 
all its matter to dust or gas. This is largely done by bacteria 
which return the material to a soluble state and is dissolved by the 
soil solution and becomes food for plants. 

Owing to its weak plasticity and great contraction when dried, 
organic matter hastens the granulation process in clay soils. It 
binds together and imparts a loamy character to light sandy soils, 
preventing drifting by the wind and erosion by the rain. It in- 



Obganic Matter in Soil 77 

creases the moisture-holding capacity of a soil and improves its 
power to resist drought. It makes soils warmer by darkening the 
color and thus increasing their absorption of the heat of the sun. 
It provides plant food direct, and releases plant food in the soil 
minerals. Plant roots not only contribute organic matter to the 
soil but on decay leave openings which aid drainage and aeration. 
The color of the soil is not, as often supposed, a safe guide to 
the percentage of organic matter present. Some red, yellow, and 
brown soils have more organic matter than some black soils and 
are more fertile. This is notably true on the Pacific Coast, more 
so than in the east. 

TOXIC BODIES. Plants produce waste bodies which may 
become harmful or toxic to themselves and to other plants of 
allied species, unless removed or changed in character in the soil. 
The incompatibility of weeds and crops, of grass and trees, is 
due to the excretion of one plant inhibiting the growth of the 
other. The fact that some varieties of plants are not afifected 
by or even destroy the excreta of other plants is the explanation 
of the beneficial results obtained by the rotation of crops. A pure 
crystalline body has been obtained, for example, from a cowpea- 
sick soil, that was not present in the soil before cropping, which 
is exceedingly toxic to cowpeas when mixed in otherwise good 
culture medium, but this same substance is not toxic to wheat. 
These toxic bodies are fatty, nitrogenous or non-nitrogenous or- 
ganic bodies, unstable and changing rather easily by oxidation 
into harmless or even beneficial bodies. Bacteria aid in their 
oxidation or reduction. They are especially apt to form where 
the aeration is deficient in the soil, as in an overwet soil, and are 
benefited by better aeration by means of thorough underd raining. 
Cultivation, if not so deep as to stir up the subsoil, tends to hasten 
oxidation and the destruction of these bodies. The necessity for 
guarding against toxic bodies is shown by such experiences as 
these. Peat soils have given over 400 bushels of potatoes the 
first year, but in two or three years the yield has dropped to 
about 40 bushels per acre, although the fertility as regards barley 
was not noticeably affected. Flax cannot be maintained for more 
than two or three years continuously, yet the flax-sick soil is not 
sensibly injured for producing wheat and other crops.. Such soils 
are not worn out, but are sick, poisoned by the excreta from the 
crops. The best way to avoid this poisoning of soils by toxins 



78 Soils of California 

is to avoid the continual growing of a crop in the presence of its 
own excreta, products of decay, etc., or, in other words, by the 
rotation of crops. 

LIFE IN THE SOIL. A fertile soil fairly hums with activ- 
ity. Myriads of forms of life are at work, changing, breaking 
down, building up. Some are beneficial, some harmful, and some 
simply neutral or harmless. A vast number of animal and vege- 
table organisms live in the soil, giving it a flora and fauna scarce- 
ly less complex than that which appears above the surface. Soils 
in which crops grow have been formed by rock decay and plant 
growth. The mineral portion comes direct from the rock, the 
humus and other organic constituents have come from living 
bodies, most of them of microscopic size. The greatest scaven- 
gers of the soil are those bacteria that work over and change re- 
mains of plants and animals. Some of these change and purify 
the soil while the crop is growing and after the crop is harvested. 
Other forms of bacteria bring about the production of substances 
very toxic to plants. 

Bacteria are intimately associated with many of the normal 
processes going on in the soil and soil solution. They are the 
most important of all the microscopic forms of vegetable life, 
for the growth of the higher food plants is absolutely dependent 
upon their presence. They have many functions, the most import- 
ant one being that of making soluble the material used as food 
by the higher plants. They are transformers, not producers, of 
the fertility in the soil, for they add no plant food but render 
available that which is already there. The success of agriculture 
depends largely upon the regulation of the growth of bacteria, for 
without them the soil would yield no crop. The relation of the 
soil to crop production involves the growth of these low forms of 
vegetable life, and the most successful farmer is the one who 
consciously or unconsciously secures the best conditions for their 
growth. These minute plant organisms remove dead animals and 
plants from the soil by decomposition, fermentation, etc., produc- 
ing the so-called self-purification of the soils. Without them the 
soil would soon be clogged with the remains of past animals and 
plants. 

KINDS OF BACTERIA. There are a number of excellent 
works on agricultural bacteriology^ and it is not necessary to go 
into details of their structure and classification; but onlv to note 



Organic Matter in Soil 79 

in a general way their relation to soils and soil building. Bac- 
teria may be divided into two classes, those that are beneficial to 
food plants and those that are injurious. They are exceedingly 
minute, some being so small that 25,000 laid side by side would 
only occupy a line an inch long. A single drop of milk may con- 
tain 100,000,000. They multiply with extreme rapidity, a single 
bacterium if unchecked could increase to 17,000,000 of offspring 
in twenty-four hours, and in five days of unchecked reproduction 
of all the descendants, could fill the oceans. This fecundity is 
however checked by lack of food and by the poisons they secrete 
killing themselves. The round forms are called micrococcus, the 
cylindrical bacillus, the curved vibrio, spirilli, etc. They are min- 
ute unicellular vegetable organisms multiplying generally by di- 
vision of the cell, but some also multiply by spores which can 
endure prolonged drying and extreme cold. Those that flourish 
only in an abundant supply of oxygen are called aerobic; those 
that require little or no oxygen are called anaerobic. The aerobic 
forms are generally beneficial to agriculture, while the anaerobic 
are generally injurious. Their names and kinds are already legion 
in number, and each seems to have its own work to do, and its 
own chosen field to work in, and to act its part in the intention, 
purpose and design of the Universe. 

The bacillus mycoidcs occurs constantly in surface soils and 
is present in natural waters and is one of the most active of the 
ammonia makers. The beggiatoa or sewage fungus reduces sul- 
phates with the evolution of hydrogen sulphide and the depositing 
of free sulphur within their cells. The saccharomycctes or yeasts 
derive nitrogen from organic substances and salts of ammonia 
and carbon from organic matter. The food of the bacteria con- 
sists of organic matter with certain necessary minerals. These 
minerals are phosphoric acid, potash, and lime. The presence 
of oxygen is necessary. When it is absent or reduced to a low 
percentage the nitrification of the soil by bacteria stops. A base 
with which the nitrous or nitric acid formed may unite is neces- 
sary, such as carbonate of lime or a small per cent of alkali. An 
excess of alkah prevents nitrification of the soil. A few bacteria 
draw their nourishment direct from the air, forming carbonate 
of ammonia and carbonic dioxide. The particles of rock decom- 
posed by atmospheric agencies are at once covered by this micro- 
scopic vegetation which produces organic acids which help to 
dissolve the particles of rock and cause them to crumble into dirt. 



80 Soils oi' California 

Some bacterial secretions form organic compounds with minerals 
as when lime is converted into calcium acetate, calcium formate, 
malate, butyrate, etc., while othre bacteria in turn break these 
compounds up into others. 

MOISTURE. Bacteria demand moisture. A decrease in 
moisture decreases their activity. They thrive or languish also 
according to the concentration of the soil solution. Too high a 
concentration checks their growth or kills them outright. They 
thrive best at optimum moisture. 

TEMPERATURE. The most favorable temperatures range 
from 70 to 110 degrees F. Thus their action is largely limited 
to summer temperatures. Dessication, as in desert regions, re- 
tards their activities and thorough air drying of a soil paralyzes 
the bacteria. 

NITROGEN FROM THE AIR. Certain low forms separate 
nitrogen from the air and from organic substances and combine 
it with the potash, soda, etc., in the soil, but they cannot do this 
unless the air penetrates the soil thoroughly. Their action is 
confined largely therefore to the upper three feet of the soil, and 
stores of insoluble nitrogenous material rest in the subsoils pre- 
served from oxidation until they are brought to the surface. Nitri- 
fication takes place deeper than six feet in many of the porous 
well-ventilated soils of the arid and semi-arid regions of the west. 
FAVORABLE AND UNFAVORABLE CONDITIONS. 
Bacteria are much more numerous in some soils than in others. 
The structure, tilth, and drainage of the soil determines largely 
whether the aerobic or the anaerobic forms are to flourish. Each 
soil possesses but one organism capable of oxidizing ammonia. 
Soils from one locality have always the same kind of nitrifying 
ferment. Soils from distant and different lands contain nitrify- 
ing organisms which differ from one another in some respects. 
The upper layers of the soil are exceedingly rich in bacteria but 
they diminish rapidly with depth and at four or six feet largely 
disappear except in the soils of the arid and semi-arid regions. 
Bacteria grow most freely in arable soil containing considerable 
humus, or rich in organic matter. In these the number becomes 
very large — from 1,000,000 to 5,000,000 bacteria per gram of 
surface soil. 

The more vigorous the decomposition changes, the higher 
the fertility of the soil. Black marsh soil shows the highest rate 



Obganic Matter in Son, 81 

of decomposition, clay soils show less, and sandy soils the least 
rate. If a soil is acid bacterial activity is checked, while the ac- 
tivity of moulds and larger fungi are increased. The physical 
conditions of the soil must favor decomposition. Hard packed 
soils are inferior to looser soils in this respect. Where oxygen 
(air) cannot penetrate the soils they become sour or acid, check- 
ing bacterial activity. Lime may aid in neutralizing this acidity, 
but aeration will do more. Sandy soils contain less micro-or- 
ganisms than the loams and clays. Compact clays and loams 
exclude air, checking nitrification by bacteria. Water logged 
soils contain but few bacteria. 

HIGHER FUNGI. Molds, mushrooms, fungi of all kinds, are 
agents in the decomposition of vegetable matter so that it may be 
incorporated in the soil, and be used again in the economy of 
nature. Some of these may be beneficial to food plants, but 
their products or excreta are often detrimental and toxic. The 
thread-like roots (mycelium) are able to push between wood fibres 
and between minute voids in the mineral particles of the soil. The 
molds are not so rich in nitrogen as the saccharomycetes, or the 
bacteria, and cannot assimilate nitrogen from the air. They de- 
rive carbon from a great variety of organic substances. They 
flourish only on the surface of the nourishing material and do 
better in a sHghtly acid medium than in one that is slightly alka- 
line. As already stated, if the soil is acid, bacterial activity is 
checked. It is evident therefore that the activities of molds and 
the larger fungi are then increased. They break down woody 
matter, facilitating the work of decay bacteria. They produce 
the dark colored matter which gives soils rich in vegetable ma« 
terial their dark color. The necessary mineral materials for their 
growth are phosphoric acid, potash and lime. 

There are humble plants, such as lichens, mosses, ferns, etc., 
which thrive upon what seems to be bare rock. The lichens 
have no true roots but spread their thin substance over the rocks 
and secrete acids which etch and dissolve the mineral matter, and 
the mosses take up the work where the lichens leave off, while 
the ferns take advantage of the thin soil left by these predecessors 
in every tiny crevice and gain a foothold. These humble plants 
shade the surface of the rocks and retain moisture which aids in 
the further decomposition of the rock and its conversion into soil. 
ENZYMES, or unorganized ferments, play a very important 



82 Soils of Calxfobnia 

part in the fermentation of manure and the preparation of it for 
its best efifects on certain soils. This fermentation does not pro- 
ceed well with too much aeration, hence the need for compacting 
a very loose soil. The subject of enzymes, however, belongs to 
the study of agricultural chemistry rather than to soils. 

HUMUS. The active principle of vegetable mould is called 
Iu())iiis. a general term for products of the decomposition of vege- 
table matter no matter what the special agent may be. It is the 
chief depositor}' of nitrogen, which is the most costly as well as 
most necessary of all plant foods. Vegetable matter decomposes 
under the action of bacteria, molds, and enzymes. The composi- 
tion of humus has not as yet been definitely determined, as it is 
a mixture of many substances mostly acid. Sawdust humus con- 
tains one to two per cent of nitrogen ; oatstraw humus contains 
from two to four per cent ; clover humus from four to eight ; and 
meat scrap humus from eight to nine per cent of nitrogen. The 
humic acid in black soils is almost exclusively in combination 
with lime. The decay of humus is most rapid in drained and 
open soils. Clay promotes the accumulation of humus. Few 
upland arid soils contain over 0.4 per cent of humus, but this 
humus is richer in nitrogen than the humus of regions of consid- 
erable rainfall. The chief functions of humus are to modify, 
the physical conditions of the soil with reference to texture, mois- 
ture, absorption of heat, and to hold in suitable form the nitro- 
genous principles of vegetable matter ; but it is not assimilated 
directly itself. It makes soils lighter and of better tilth, enables 
them to absorb more moisture, and makes them warmer. 

ANIMAL LIFE IN THE SOIL. Earthivonns not only obtain 
nourishment from the organic matter of the soil, but take in the 
inorganic. They pass the soil through their bodies leaving it in a 
granulated condition in the "casts" which they deposit. It is esti- 
mated that in a favorable soil in a humid climate as much as 
eleven tons of dry earth per acre passes through their bodies 
and that 0.18 per cent of their secretions consists of soluble ni- 
trates in the form of ammonia. They modify the soil mechan- 
ically by bringing to the surface particles of the subsoil ; the holes 
left by them increase aeration and drainage, and the soil is made 
more porous and easily pulverized. They aflfect the soil chem- 
ically by acid and alkali reactions as the soil passes through their 
bodies, leaves and other organic material being converted largely 



Organic Matter in Soil 83 

into humus. Finally the bodies of the worms themselves become 
fertilizing material and food for the bacteria and plant roots. 
Worms naturally seek heavy, compact, and moist soils where 
they are of the most benefit ; the sandy soils which do not need 
them contain few. Ants with their busy colonies bring soil from 
the depths and heap it on the surface, giving drainage, aeration, 
and mixing the soil with subsoil. Beetles and a myriad of other 
burrowing insects and animals cause movement of the soil par- 
ticles and aeration and drainage and incorporate a considerable 
amount of organic matter with the mineral matter present, and at 
last contribute their own bodies to the sum total. 
ACID SOILS. Soils rich in decaying vegetable matter may 
show a distinct acid reaction. Even very acid soils contain but 
little acid, or acid salts, soluble in water. The humic and ulmic 
acids and their salts are chiefly responsible for the harmful acidity 
of soils. Acidity exerts a marked influence upon the 
crop-producing power of the soil, as it affects both its physical 
and chemical condition, (1) through its action upon the micro- 
organisms which in turn modify the physical condition, and (2) 
by the direct action of the acids upon the tender rootlets. Crops 
grow best when the soil is neutral, that is, neither acid nor alka- 
line. Lime and limestone are the best correctives. Soils in the 
arid regions are more apt to be alkaline than acid. 



CHAPTER XII 

SUBSOIL. SOIL MOVEMENT. SOIL 
PERMANENCY 

SUBSOIL. This is the part next below the surface soil, and 
the distinction between soil and subsoil lies almost wholly in the 
color and texture, the composition being very much the same, 
as a rule. Generally the subsoil is soil in the process of mak- 
ing, or raw unfinished soil, as the surface soil is often only the 
weathered or rotted subsoil ; and the subsoil in turn is only a 
phase of the rotted bedrock below. The character of the sub- 
soil afifects the water-holding capacity of the soil above. Thus 
a gravel subsoil, or sand subsoil, gives perfect drainage, while 
a clay subsoil interferes with drainage. The nature of the sub- 
soil affects the productiveness of the soil. An impervious sub- 
soil, or a very loose sandy one, confines the productive zone to 
the top soil. An old English ballad says : 
"Clay on sand is money in hand ; 
Sand on clay is money thrown away." 
While this may be true in the humid climate of the "right 
little, tight little island" it is untrue in an arid climate. Climate 
modifies the relation of the subsoil to the soil. In humid regions 
of large rainfall and seepage, the subsoil is finer and more com- 
pact than the soil from the washing downward of the finer par- 
ticles. In the arid regions the subsoil is inclined to be coarser 
than the soil above. In humid regions the subsoil is less produc- 
tive than in the arid regions owing to the greater amount of 
leaching. Occasional deep plowing brings some of the subsoil 
to where it is exposed to the atmospheric weathering, and the 
action of plant roots, and humus, so that it becomes in time 
surface soil. Most soils formed under arid conditions are sandy, 
and there is little or no clay to be washed down into and com- 
pact the subsoil, the result being that air and water circulate to 
greater depths than in the soils of the humid regions. The dis- 
tinction between soil and subsoil is slight in the arid regions ; or 
the soils are so deep that there is no subsoil within the depths 
which tillage can be made to reach. There are exceptions to this 



Subsoil Soil Movement Soil Permanency 85 

rule in the arid regions, as in the case of marsh, swamp, lacus- 
trine soils, or where bedrock comes close to the surface. In the 
arid regions the farmer may be said to own three or four farms, 
one above another, as compared with the same acreage east, for 
he finds hop roots going down as much as fourteen feet without 
lateral expansion ; grape roots going down twenty feet ; alfalfa 
twenty-five to thirty, etc. Another illustration is the fact that 
the earth from cellars and house foundations is fearlessly put onto 
gardens on which fruit, flowers, and vegetables grow in the first 
year. The irrigator also levels slopes, hillsides, and terraces 
with no idea of discrimination between soil and subsoil, and the 
results justify his action. Calcareous or limey subsoils enable the 
farmer to enrich the surface by deep subsoil plowing. In shallow 
soils the nature of the subsoil should be closely observed. 

SOIL MOVEMENT. The predominant factor in the pro- 
duction of a crop is the amount of available mineral plant nutri- 
ents in the soil, joined to the physical condition of the soil. For 
years the idea has prevailed that a given field or soil mass stays 
in place indefinitely and without changes, except such as are pro- 
duced by cultural methods. This is not at all the case. It is 
now known that the soil must be dealt with as a living thing in 
the sense that it is ever in motion. The root of the plant is al- 
ways in action, while the plant lives ; the soil solution (the blood 
of the soil body) is always in motion, and if it stops and is stag- 
nant the soil is dead ; the soil atmosphere is constantly in motion 
and changing, for the soil must breathe ; the life of bacteria, etc., 
in the soil affects its sanitary condition or health. Soil is not 
a dead, inert mass, but in constant action. The particles are in 
motion from freezing and thawing, and every change in the mois- 
ture content is accompanied by motion. The activities of insects, 
earthworms, burrowing animals like beetles, gophers and moles, 
are constantly translocating soil material. Ants bring about 
large transfers from lower to higher levels, and their borings 
admit air and water to the deeper lying portions, promoting 
further chemical and physical changes. The angleworm or earth- 
worm is one of the most important of the soil builders, loosening, 
aerating, fining and draining the soil and subsoil. A soil is not 
dead, but teems with life and hums with activity. Countless 
organisms visible only to the microscope are ever at work soil 
building, soil destroying, and soil changing. Water action in 



86 Soils of California 

translocation is restricted only by the fact that water can run 
down hill only, but the wind is constantly in action and blows 
uphill as well as down, and sidewise. It is a striking fact that 
articles left lying on the ground gradually sink below the sur- 
face. Even a layer of ashes or lime will sink as a layer and be 
found a few years later as a distinct stratum below the sur- 
face. The slow and unnoticed drift of materials backward and 
forward by wind and water are ever afifecting the soil. The 
accumulations of dust, so evident to every housewife, are un- 
noticed in the field by the average farmer, yet they are very 
important, for they amount to several tons per square mile, or 
section of land each year. 

It is a fact that must be taken into consideration that the 
soil of a particular field, especially one under cultivation, is not 
just the soil that was there a few years ago, or just the soil that 
will be there a few years from now ; and that this movement at 
normal is beneficial and an important factor in maintaining fer- 
tility, but when abnormal, as under wind erosion, etc., it is bane- 
ful. The control of the wind action is met by windbreaks, cover- 
crops, etc., and that by water erosion by forestration, rotation 
schemes, cultural and other methods. The persistence of a soil 
is the persistence of the soil layer rather than of the individual 
particles, just as the maintenance of our own bodies consists in 
maintaining its health and form while the individual particles of 
which it is composed are forever changing. Soils are always in 
the process of change, and soil conditions are not static, therefore, 
but dynamic. 

SOIL DETERIORATION. Soils vary greatly in their 
power of endurance. Most soils deteriorate through neglect and 
insufficient and injudicious cultivation. They deteriorate even 
with fairly good treatment under the one-crop system, whether 
it be wheat, corn, cotton or tobacco. They frequently deterior- 
ate through erosion where the top soil is removed, leaving the 
unwcathered subsoil as the medium of growth. A complete dry- 
ing out of the soil for a prolonged period usually brings beneficial 
changes. Infertility is often due to the presence of toxin bodies, 
and other causes already mentioned. 

SOIL PERMANENCE. Many gloomy predictions have 
been made regarding the probable failure of the soil to support 
the increasing population of the earth. Such predictions seem 



Subsoil Soil Movement Soil Permanency 87 

absurd to soil students. Proper drainage, cultivation, aeration, 
rotation and fertilization maintain the sanitary conditions in the 
soil, and renew the productive capacity of so-called dead and 
zvornout soils. If the practice of agriculture has ruined land, 
the science and art of agriculture must restore it. If the youth 
of the civilized nations were required to take a three years' course 
in agriculture instead of their militia training, the talk about 
wornout soils would die out with the talk of the necessity of 
colonization for the excess population. The work of the U. S. 
Bureau of Soils alone in several states shows that there is no 
actual exhaustion of the mineral plant foods in the soils that 
were called exhausted, wornout, and impoverished, because agri- 
culture had declined there. Soils are not impoverished of their 
mineral plant food contents within the finite range and experi- 
ence of human knowledge. The Bureau has proven that a mere 
change in cultural methods has worked wonders, and in five 
years many of the so-called exhausted soils yielded better than 
formerly. 

The older agricultural soils of Europe and Asia contain the 
same common rock-forming minerals of the newer soils of the 
United States, and there is no essential difference in their chem- 
ical composition. The lands of Europe have been occupied for 
a thousand years without a noticeable reduction of the plant 
food element as compared with the newer soil of this country. 

Many sections of China have undoubtedly supported an agri- 
cultural population for centuries longer than the soil of Europe, 
but there is no sign of deterioration of these soils. The soils 
of Europe are not only not wearing out but are improving in 
their yield. This increase is due to better methods of cultiva- 
tion, care in the selection of seed, increase of livestock, use of 
scientific fertilizers, proper drainage, aeration, systematic rotation 
of crops, etc. It is aided by the fact that one family and its 
descendants occupy the same farms one generation after another, 
and become intimately acquainted with each soil and its peculiari- 
ties. The fertility of the soil can be temporarily impaired, but 
soils do not wear out in the sense that this term has been used 
in the past, and there is no permanent wide-spread exhaustion 
or deterioration of the soil. The soil will not be exhausted of 
any one or all its mineral food contents, but is safe as a national 
asset as a means of feeding and clothing mankind for the ages 
yet to come. 



CHAPTER XIII. 
CLASSIFICATION OF THE SOILS 

In any one of the provinces of California will be found soils 
derived from the same materials formed through the same agen- 
cies, and having certain chemical and physical characters in com- 
mon, but dififering in texture, and exhibiting all gradations from 
clay to gravel. The soil minerals found in the soil provinces do 
not differ materially in character, but the soil peculiarities of 
each province are the result of different agencies, such as climate, 
topography, etc. It makes a difference whether the soil is in a 
humid, arid, or semi-arid province. The differences in the prop- 
erties of the several grades of materials, or size of the mineral 
particles, gives rise to various soil types, classes, or groups. 

SOIL SERIES. A common name taken from some typical lo- 
cality is given to each soil series, such as the Sacramento series, 
Imperial series, or San Joaquin series, showing types formed in 
the same general way. 

SOIL CLASSES. All those soils having the same general tex- 
ture, no matter how derived, constitute a soil class, as the sandy 
loams, sands, loams, and clays. Every farmer knows that there 
is a great difference between sand and clay, that they must be 
handled different, and are suited to different crops ; but he does 
not know always that the cause is due to the different size of the 
soil units. 

SOIL PARTICLES. The grade of material entering into a 
soil is determined by the size of the particles, the measurements 
being in millimeters. A millimeter is the thousandth part of a 
meter or .001 m, and is equivalent to the 0.03937 part of an inch. 
It is denoted by writing mm. after the figures as 1 mm. is a milli- 
meter. The standards are as follows : 

Gravel 2. to 1. mm. 

Coarse sand 1. to 0.5 mm. 

Medium sand 0.5 to 0.25 mm. 

Fine sand 0.25 to 0.1 mm. 

Very fine sand 0.1 to 0.05 mm. 

Silt 0.05 to 0.005 mm. 

Clay 0.005 to 0.0000mm. 

Material larger than 2 mm, or 0.08 of an inch, is classified 



Classification of the Soils 89 

as pebbles, cobbles, boulders, etc., and is not included in the soil 
analysis, but described in connection with the land. 

The combination of different percentages of the particles or 
units, or the combination of these units in different proportions, 
form the soils known as sand soil, fine sand soil, sandy loam soil, 
fine sandy loam, loam, silt loam, clay loam, and clay soils. There 
are also phases of these soils, as gravelly sands, loamy sands, 
stony loams, or stony clays, which may in certain provinces be 
included in a group, and in other provinces be set aside as subor- 
dinate soils of little agricultural value. 

SOIL NAMES. All those soils having the same general 
texture, no matter what their derivation, have the same class name, 
as sandy loam, silt, fine sandy loam, etc. They are named accord- 
ing to the relative proportions of the different particles or units 
entering into their composition. The rules for naming are as 
follows : 

Soils containing : 

(1) Less than 20 per cent of silt and clay together, are 
called : 

COARSE SAND, if they contain more than 25 per cent 
of fine gravel, and less than 50 per cent of any other grade. 

SAND, if they contain more than 25 per cent of fine gravel 
and medium sand, and less than 50 per cent of fine sand. 

FINE SAND, if they contain more than 50 per cent of 
fine sand, or less than 25 per cent of fine gravel, coarse and 
medium sand. 

VERY FINE SAND, if they contain over 50 per cent of 
very fine sand. 

(2) From 20 to 50 per cent of silt and clay, are called: 
SANDY LOAM, if they contain over 25 per cent of fine 

gravel, coarse and medium sand. 

FINE SANDY LOAM, if they contain over 50 per cent 
of fine sand, or less than 25 per cent of fine gravel, coarse and 
medium sand. 

SANDY CLAY, if they contain less than 20 per cent silt. 

(3) Over 50 per cent of silt and clay are called: 
LOAM, if they contain less than 20 per cent clay and less 

than 50 per cent silt. 

SILT LOAM, if they contain less than 20 per cent clay, 
or over 50 per cent silt. 



90 Soils of California 

CLAY LOAM, if they contain 20 to 30 per cent clay, or less 
than 50 per cent silt. 

SILTY CLAY LOAM, if they contain 20 to 30 per cent 
clay, and over 50 per cent silt. 

CLAY, if they contain over 30 per cent of clay, etc. 
HEAVY AND LIGHT SOILS. The sands, sandy loams 
and fine sandy loams are generally referred to as light soils. The 
loams, silt loams, clay loams, and silty clay loams are referred 
to as heavy soils. This refers not to the weight per cubic foot 
of the soil, but to the draft required in plowing, cultivating, etc. 
Fine material of this kind is held in a plastic or coherent condi- 
tion and requires more power to plow and cultivate than it does 
on loose or only slightly coherent soils of the sandy groups. The 
yields are also generally larger and more bulky on the loam and 
clay groups than on the sandy groups and this requires heavier 
teams for harvesting the crops as well as to prepare them. 
DEPTH CONSIDERED. In naming a soil the texture of 
the surface soil and of the subsoil to a depth of three feet in the 
humid states and six feet in the arid states is taken into consider- 
ation. There are soils that have a sandy surface soil and a clay 
subsoil, and occasionally there is a clay soil that has a sandy sub- 
soil, affecting the adaptability to crops. When a soil is referred 
to by name as the Imperial sandy loam, the term soil in this 
sense includes both the top and the subsoil. In sampling soils, 
the top soil and the subsoil are kept separate, and if the subsoil 
shows two layers of different texture these are separated also. 
SOIL SERIES. Where soils have a common origin, and 
differ only in texture and are alike in color and physical prop- 
erties other than those affected by texture, they are arranged in 
what is called a scries, having the soil generic name with quali- 
fying textural terms. We have for example the Placentia soil 
series, named for the type locality around Placentia, in Orange 
County, California. This series is divided into classes known 
as the Placentia sandy adobe, Placentia sandy loam, Placentia 
fine sandy loam, Placentia loam, Placentia loam adobe, Placentia 
clay loam, and Placentia clay loam adobe. The same type of soil 
receives the same name, and members of the Placentia series are 
found around Riverside, Redlands, Perris. and other localities re- 
mote from the type locality. Members of the Hanford series are 
found also around Los Angeles and San Bernardino. 



Classification of the Soils 91 

Other things being equal, the water holding capacity of the 
soil will vary as the texture varies ; the light sandy types holding 
on an average not over four per cent of water, while the clay 
members may hold as high as twenty per cent of moisture. This 
difference in moisture creates a corresponding difference in the 
soil atmosphere and oxidation is usually more rapid in the sandy 
than in the clay members of a series. The effect of these differ- 
ences of soil texture upon the adaptation of soils to crops and 
upon crop production is well known, and is stated under the 
descriptions of the soils. The iuoisture of a soil is defined as fol- 
lows : zi'ct, when water drips from a piece held in the hand without 
pressing ; moist, when water drips from a piece pressed in the hand ; 
fresh, when no water drips from a piece pressed in the hand, 
although it is evidently present ; dry, when there is little or no 
trace of water present ; and very dry, when the soil is parched. 
The depth of soil is indicated in terms which have their equivalent 
in inches, thus, I'ery shallozv means less than six inches ; shalloiv 
means six to twelve inches ; moderate means twelve to twenty- 
four inches ; deep means from twenty-four to thirty-six inches ; 
and very deep anything over thirty-six inches. In doing the field 
work of classifying soils, all features are taken into consideration 
which in any way appear to influence the relation of the soil to 
crops. The classification is based mainly but not wholly upon the 
physical properties and conditions of the soil. Any chemical 
features such as deposits of marl, of highly calcareous soils, or 
of highly colored soils is considered. The character of the na- 
tive vegetation, or its absence, and the condition of crops growing 
is noted as a prominent factor. The topography of the country 
is often a safe guide in outlining the boundaries of soil conditions. 

Local variations in the character of the soil less than a quar- 
ter of a mile in extent are generally ignored, unless this varia- 
tion constitutes a very prominent feature, such as a strip of 
meadow land along a stream, or unless there are a number of 
small areas by which character is given to the district, such as 
rocky areas, small each, but extending in the aggregate over 
large areas. For example, Meadow Land is not only a distinc- 
tive feature, but it is a very fine sediment of silt and very fine 
sand, which is easily recognized as distinct from the other soils 
of the valley. Loam is a grade coarser than the meadows, and 
the character of the vegetation and the relation of crops in the 
field is very marked. In some places the classification of the 



92 Soils of California 

soils has to be made mainly from the distribution of the native 
vegetation, where the different classes of soils vary but little in 
their physical and chemical properties, but show a very great 
difference in their native vegetation and in their adaptation to 
crops. The survey of alkali lands involves special determina- 
tions and observations in the field. There should be a soil map, 
the alkali map, the underground water map, and where black 
alkali, or sodium carbonate exists in appreciable quantities, a 
separate map showing the distribution and percentage of this 
pernicious substance. As a rule, the clay soils on the flats and 
draws contain the greater amount of alkali, the loam soils next, 
then the sandy loams, and finally the sandy soils. This is due 
partially to texture and its influence on the drainage, and par- 
tially to the physiography of the country as to drainage. 
ADAPTATION OF SOIL TO CROPS. The influence of 
abrupt topographical changes, as our mountain ranges and ele- 
vated plateaus, tend not so much to modify the character of the 
soil, as they do the character of the crops that may be raised to 
advantage. The slope and the elevation has the effect of adapt- 
ing the land to special crops, and call for different methods of 
soil management. The climates of each province are widely 
different and affect the class of crops that may be raised, 
as the desert sand may be well adapted to date culture, 
while sands in a colder climate would not be. There is remark- 
ably little true clay in California such as is found in the east, 
but sands, loams and silts predominate. Some soils have adobe 
properties which are unusual in the east. The soils of the west 
are generally freer from toxic organic bodies than eastern soils, 
and are capable of producing maximum crops under irrigation 
and intensive culture. Plants develop a much deeper root sys- 
tem than on the soils of the east. The fact that there is little 
difference in texture between the soil and subsoil, that rains are 
infrequent, the atmosphere dry, and the surface evaporation rapid, 
enables the farmer to maintain a more efficient surface dry mulch, 
making it possible to produce good yields of crops with remark- 
ably light rainfall, and frequently without any rainfall at all, dur- 
ing the growth of the crop. The climate limits broadly the zone 
or area in which certain field crops may be grown, and affect 
the yield and quality of the crop. In California, the arable lands 
vary from below sea level to elevations 6,000 feet above. The 
greatest precipitation comes in the winter season. There is a 



Classification of the Soils 93 

wide difference in the provinces in the relative humidity and sun- 
shine, as there are differences in the range of temperatures daily 
and seasonal ; and there are differences in the length of the grow- 
ing season. There are also differences due to exposure, slope, 
etc. All of these points have to be taken into consideration in 
determining the special fitness of a soil for any particular grade, 
quality or kind of product. 



PART V 

CHAPTER XIV. 
KEY TO CALIFORNIA SOILS 

The following artificial key to the soils of the state gives a 
method for identifying or classifying a soil tentatively from its 
origin, appearance, or position, and finding out what series it be- 
longs to or most closely resembles. While it covers the principal 
series it is impossible to include all the purely local soils and their 
variations. These may be identified locally by comparing them 
with other members of the same class. 

Thus if a soil is recognized as a silty clay loam, a comparison 
of the soils described under that head will show wherein it 
resembles or differs from those already identified and classified, 
and whether it belongs to an established series or not. 

The broad natural divisions are based on the origin of the 
soils, viz : 

A— RESIDUAL SOILS. 
B— COLLUVIAL SOILS. 
C— ALLUVIAL SOILS. 

RESIDUAL SOILS. The residual soils may be subdivided 
as follows : 

Derived from granitic rocks : Black color, Portersville series. 
Brown, Daulton. Chocolates, Arnold, red. Media. 

Derived from granites, slates and volcanic rocks : red, Sierra. 

Derived from granitic and metamorphic rocks : Pleasanton. 

Derived from granite and shale : brown, Encinal. 

Derived from sandstone : Contra Costa. 

Derived from sandstone and shale : Altamont, Santa Cruz. 

Derived from shales and conglomerate : Watsonville. 

Derived from limestone : Diablo. 

Derived from lava : Tuscan. 

Derived from metamorphic rocks : Vallecitos, 

Derived from the Red Bluflf formation : Tehama. 



Key to Caxifobnia Soils 95 

COLLUVIAL SOILS. The colluvial soils may be divided 
as follows : 

Derived from granitic or volcanic material : Dark colored, 
Maricopa. Reddish brown with clay or sand subsoil : 
Placentia. 
Derived from granodiorite or gabbrodiorite : Black from 

hornblende or mica, Sheridan. 
Derived from andesitic rocks, tuffs and breccias : Sutter. 
Derived from shale : Salsipuedes, Danville. 
Derived from sandstones, shales and shaly sandstone : 

Oxnard. 
Derived from sandstones, shales, conglomerate, and volcanic 

rocks : Sites. 
Derived from recent marine deposits : Indio. 
COLLUVIAL, modified by mixture of alluvial, valley soils: 

Dublin, Livermore, Sunol, Ulmar. 
ALLUVIAL SOILS— WELL DRAINED: 
River and stream deposits : 

Along the Colorado River bottom : Gila. 

On the Colorado delta : Imperial. 

From shales and sandstones : Yellow brown. Esparto. 

Black, Pajaro. 
On bottom lands : Orland. 
On lower benches and plains : Yolo. 
At base of foothills : Oakdale. 
On minor creek bottoms : Elder, Mocho. 
On Upper Valley Plains: 

Gravelly bottoms of intermittent creeks : Anderson. 
Upper valley floors : Arbuckle, Maywood. 
On broad deltas, cones, sloping plains : Fresno. 
River and delta plains : Hanford. 
On upland mesas : Santiago. 
On plains : Gridley. 

From Red Bluff formation : Corning, Kirkwood, 
Redding. 
ALLUVIAL SOILS— POORLY DRAINED. 

Lacustrine origin, temporary lakes : Capay. 

Coastal, drab, rushes, tules, Alviso clay. Black: sloughs 

and marine salts : Galveston clay. 
Recent stream deposits, overflowed : Sacramento, Alamo, 
Feather. 



96 Soils of California 

Swamps : Santa Rita. 

Wash from more elevated soils : Lime hardpan, Stock- 
ton. Many local soils. 

Valley plains : Red, hardpan : Madera, San Joaquin. 
(A) RESIDUAL SOILS. These are derived from the direct 
weathering of rock in place. They are gravels, sands, or clays, 
or other soils that are the actual residues or products of rock 
decay, occupying the sites of the rock masses from which they 
are derived. There may be as many kinds of residual soil as 
there are kinds of rock. They are sometimes called sedentary 
soils in place. They may be shallow and marked by abundant 
outcrops of rock, boulders and rough rock areas, or they may 
accumulate to great depth and the underlying rocks not exposed 
except where the erosion has been excessive. They generally 
contain sharp fragments of the undecomposed bedrock which 
increase in size and number downward in the soil. They are 
highly colored as a rule, usually red or yellow from the accu- 
mulation and alteration of iron salts. Thus a gray limestone may 
produce a red clay soil. They are seldom uniform in texture 
and the clays are usually gritty. They are commonly found or 
occur on rock plateaus, on plains where bedrock is near the 
surface, and in granitic, volcanic and basaltic areas. They occur 
also along the bases of mountains, foothills and covering low hills 
and rolling ridges. The texture of these soils and the surface 
slope is such that there is usually good drainage. 
PORTERSVILLE SERIES. The type locality is in the 
Frazier Valley, near Portersville, where these soils occur along 
the lower slopes of the foothills. They are derived from the 
underlying granite, but are more or less modified by alluvial 
agencies and wash. The color is generally black from organic 
matter, but may vary from dark red to brown locally. 

DAULTON SERIES. The type soil is found in the Madera 
district. They are formed by the decomposition of the granite 
and quartz rocks of the foothills. The color is brown to red 
brown. Not extensive, and generally used only for dry farming 
to grain. 

The Arnold soils of the Modesto-Turlock area occupy the 
foothills of the Sierras. These hills are of sedimentary origin 
and were once part of a gently sloping smooth ocean or lake 
bed that occupied the Great Valley. When this portion was 



Key to California Soils 97 

raised above water it was carved by erosion into its present form. 
The predominating outcropping beds of the southern hills of this 
area were very largely granitic in origin, weathering into the 
chocolate-colored soils which have no true hardpan and are un- 
derlain at various depths by the sedimentary formations from 
which they were derived. They have been greatly modified by 
rain, wind, plant life, and other agencies since first formed. 
MEDIA SERIES. The types soils are found in the Madera 
area on the high rolling foothills of the Sierra Nevada. They 
have a typical red color. 

SIERRA SERIES. The type soils of this series cover large 
areas of valuable fruit and grazing lands along the western slope 
and base of the Sierra Nevada mountains. They comprise soils 
derived from the weathering of granitic rocks, diabase, altered 
rocks, (such as amphibolites, slates, serpentine, and volcanic ma- 
terials) with a slight admixture of colluvial and alluvial material 
from the same sources. They are generally of light red to deep 
red color, and of somewhat compact structure. They occupy 
rolling and frequently mountainous districts and foothills, and 
usually support a more or less heavy growth of brush and forest 
trees. 

PLEASANTON SERIES. The Contra Costa Hills on the 
west and the Mt. Diablo Range on the north and east, in the 
Livermore area, are composed of Tertiary and Cretaceous sand- 
stones, limestones, conglomerates, and argillaceous shales, with 
granitic and metamorphic rocks. The Pleasanton series are the 
residues of granitic and metamorphic rocks and occur on the 
uplands. 

ENCINAL SERIES, The Encinal sandy loam occurs in the 
resfion of Elkhorn Slough on the southern slope of the Monterey 
Hills. It is dark brown to drab gray in color, with a whitish sub- 
soil. The soil contains sharp fragments of granitic gravel and 
shale. 

CONTRA COSTA SERIES. The type soils are found in 
the Livermore area and are derived from the weathering of the 
Tertiary and Cretaceous sandstones of the Contra Costa and Mt. 
Diablo Ranges. See Pleasanton. 

ALTAMONT SERIES. The type soils are found in the 
Livermore area, and are formed by the decomposition in place 



98 Soils of C.vlifoenia 

of the shales and conglomerates of the Contra Costa Hills and 
the Mt. Diablo Range. Sec Pleasanton. 

SANTA CRUZ SERIES. The type soils of this series are 
found in the Santa Cruz mountains and are derived from the 
weathering of shales and sandstones in place. They are red 
to dark brown in color. 

WATSONVILLE SERIES. This series is derived from 
shale, or from shale and conglomerate. They occupy low roll- 
ing ridges and hills that form the plain north of the Pajaro River. 
They are dark brown to red in color. 

DIABLO SERIES. The type is found in the Livermore area 
on the uplands, and are formed by the weathering of Cretaceous 
limestones of the Mt. Diablo range. They are brown in color. 
Fossil oysters are common in the soil in the type locality. 

TUSCAN SERIES. The type soils are found in the Red 
Bluff area, on the east side of the Sacramento Valley. They are 
shallow soils, reddish brown in color, and are formed by the 
weathering of the lava flows from Lassen Peak region. 

VALLECITOS SERIES. The type soils are found in the Liv- 
ermore area on the uplands, and are the result of the weathering 
of the metamorphic rocks of the Mt. Diablo Range. See Pleas- 
anton. 

TEHAMA SERIES. The type soils are found in the Red 
Bluff region lying above the alluvial plains along small streams, 
on the west side of the Sacramento Valley. They are derived 
from the weathering of the Red Bluff formation. 

(B) COLLUVIAL SOILS. These take their name from 
collis (a hill), as they are soils that move or creep slowly down 
moderate slopes through the action of expansion and contraction 
from heat and cold, and through the action of gravity, frost, and 
rain wash. They consist of alluvium in part from wind sweep 
and water wash, and also contain angular fragments of the 
original rocks. They consist of unassorted colluvial, or only par- 
tially sorted alluvial material formed by the soil creep, by direct 
wash from the mountain side, and by the deposit of intermittent, 
shifting, torrential streams. They occur as talus and cliff debris, 
and as avalanche and slide material. They are found on hill- 
sides, rolling and hilly uplands, on mountain slopes, on delta 
cones or fans, debris aprons, and the sloping plains of filled val- 



Key to Calitobnia Soils 99 

leys. They also occur in stream valleys as the product of a series 
of secondary fans or cones emerging from adjacent more elevated 
slopes or mesa lands. 

MARICOPA SERIES. These soils are found in many local- 
ities and are derived from a variety of rocks, but generally from 
those of granitic and volcanic character. They are generally of 
dark color and loose porous structure, well drained and free 
from alkali. 

PLACENTIA SERIES. The type locality is around the 
town of Placentia in Orange county. They are distinguished 
from the Maricopa by the prevailing reddish brown to reddish 
gray color, and in being underlain by indurated sands, shaley sand- 
stones, distintegrated granite, or by heavy compact red loams or 
clays of tough impervious adobe structure. Generally well 
drained and free from alkali, but somewhat refractory to culti- 
vation. They are widely distributed, especially in the southern 
part of the state. 

SHERIDAN SERIES. The Sheridan sandy loam is a black 
friable soil found in the Sacramento area. The characteristic 
black color is due to the large proportion of black hornblende and 
biotite mica crystals which it contains. 

SUTTER SERIES. The type locality of this series is in the 
vicinity of the Marysville Buttes. They are dark brown to black 
in color and underlain by brown or yellow loams. They are 
made up of material from the Marysville Buttes, which are com- 
posed of andesitic rocks, tuffs and breccias. 

SALSIPUEDES SERIES. The Salsipuedes loam of the 
Pajaro Valley has been washed down from the shale mountains 
and adjacent hills. It is brown in color and is underlain by loam 
or sandy loam. 

DANVILLE SERIES. The type is found in the Livermore 
area on the valley floor and is formed from the shales of the 
Contra Costa Hills and Mt. Diablo Range, as shown by the sharp 
shale fragments in the soil. It is somewhat modified locally by 
alluvial wash. 

OXNARD SERIES. This series consists of delta plains de- 
posits, colluvial and alluvial wash from the foothills. They are 
derived mainly from sandstones and shales and occur on rolling 
hills ; elevated and dissected mesa lands and plains, and delta 



100 Soils of California 

plains. They are less elevated than the Maricopa, and are lacking 
in the granitic material of that series. They are generally dark 
colored, and underlain by heavier subsoils which do not have 
the red color and adobe structure of the Placentia series, which 
occupy similar topographic positions. 

SITE SERIES. These are found on the slopes and across 
the narrow valleys of the outer range of hills forming the western 
edge of the Sacramento Valley in the Woodland area. They are 
generally brown in color, with variable subsoils and are derived 
from the sandstones, conglomerates, shales, and volcanic rocks 
of the Coast Range. 

INDIO SERIES. These soils are wholly wash from the 
surrounding mountains of the Riverside and San Jacinto ranges. 
They range from sea level to about 250 feet below sea level. 
The surface of the Coahuilla Valley is covered with small shells, 
showing that the soils were deposited under water and are the 
weathering of recent marine deposits. They are all very sandy, 
loose, friable, light colored, and show particles of quartz, mica, 
granite, and volcanic ash, and are more or less wind blown. 
COLLUVIAL, MODIFIED BY MIXTURE OF ALLU- 
VIAL. Some soils are distinctly colluvial in origin and yet 
are modified by considerable quantities of alluvial material 
washed into them. The DUBLIN, LIVERMORE and SUNOL 
soils of the Livermore area are valley soils, having largely a com- 
mon origin and position but dififering in character and crop value. 
The Dublin is black in color, and derived from shale ; the Liver- 
more is brown in color and poorly drained ; the Ulmar is brown 
in color and marked by hogwallows. Other characteristics are 
given in the local description. The Sunol is a brown loam carry- 
ing slate fragments, and has a clay loam subsoil. 
(C) ALLUVIAL SOILS. These are recent deposits in val- 
leys, on flood plains, bottom lands, and deltas of the detritus, 
1)rought down chiefly by water. This includes recent alluvium, 
marsh and swamp deposits, clays, and loess and adobe in part. 
Such deposits are more or less distinctly stratified or bedded. 
Their productiveness is due to their fine texture, their frequent 
renewals by deposits from flood waters, and the variety of ele- 
ments of which they are composed. They are the soils of the 
valleys, flood plains and lake borders, past and present. They 
occur all along the main stream courses, especially in the lower 



Key to California Soils 101 

lands, where during flood season the water usually leaves the banks 
and spreads over the flat lands adjoining. The sediments carried 
down from the mountains and higher ground are spread out over 
the bottoms in thin layers during flood time. Nearest the stream, 
or wherever the current is swiftest, the coarser grades of sand 
and gravel are deposited and build up the coarser textured soils. 
Further away from the stream, or wherever the current is slug- 
gish, the finer sediments like fine sand, silt and clay are deposited, 
building up the finer textured soils. Along the larger rivers the 
material may show distinctly that it comes from the mountains 
of the interior. Along the smaller streams the soil consists of 
the wash from the adjacent foothills and plains soils. They often 
occur in long continuous bodies, paralleling the courses of present 
or former streams, along the smaller intermittent foothill and 
plains water courses, and as distinct alluvial fans where the 
smaller streams flow into basins. Some are deposited in inter- 
mittent lakes, some in the swamps at the margins of lakes and 
some in the swamps and bayous covered by ocean tides. Many 
of the low-lying members are subject to overflow, or the drain- 
age may be deficient owing to the flatness of the surface, char- 
acter of the subsoil, or to other local causes. Being of mixed 
origin, their general character may vary from one extreme to the 
other, both as regards physical and chemical composition. In the 
upper portions of the valleys, where the slope is steep and the 
velocity of the waters is high, cobbles and gravels are dominant. 
As the slope decreases, first coarse and then fine sand will be 
prominent, while still lower down the finest sand, then silt, and 
finally clay will dominate. As streams in flood vary in velocity 
from time to time, deposits of dififerent texture will often alter- 
nate with one another on the flood plains. This is a distinguish- 
ing mark of alluvial soils and is noticeable on terraces, benches, 
and mesas, due to the elevation of the land or to the depression 
of the river channel. On the lower slopes of hills bordering allu- 
vial valleys the colluvial slope soils often alternate with the allu- 
vial deposits. The alluvial soils may be divided in the two nat- 
ural divisions of well drained and poorly drained, and these in 
turn subdivided according to their principal characteristics. 

GILA SERIES. These soils are formed from the deposits of 
the Colorado River in its annual overflow. They are red brown 
in color, loose and incoherent. 



102 Soils of Cajlifobnia 

IMPERIAL SERIES. They occur in the Imperial Valley, 
which is a portion of the Colorado River delta. This region was 
once occupied by a northern extension of the Gulf of California 
into which the Colorado River poured its sediment-laden stream, 
building up an extensive submarine delta. Later the region be- 
came a lagoon shut off from the sea. The marine and lagoon 
phases are marked by extensive beach line deposits. The lagoon 
phase fluctuated between salt and brackish water stages and was 
later replaced by an arid basin that at its lowest point was 260 
feet bclozi' sea level. Since that time repeated overflows of the 
river have carried suspended sediments into the basin, burying the 
older deposits at various depths. The surface materials from 
which the soils are derived are not continuous, but form thin 
irregular lenses of sediment. The chief agent now at work is 
the wind, which excavates, transports and deposits a large quan- 
tity of material annually. The greater proportion of the soils 
consist of clay and silt, the heavier soils predominating. They 
differ from the Gila series in being underlain by heavy sediments 
of close nature. 

ESPARTO SERIES. These soils are derived from material 
transported by the minor streams of the foothills of the Coast 
Range, and are of recent origin. They originate from shales, 
sandstones and clays of the lower range of hills, and overlie the 
older formations of the valley plain. They are generally yellow- 
ish brown in color. 

PAJARO SERIES. These are derived from shales and 
sandstones, with an admixture of igneous and crystalline rocks. 
They extend from the river to the hills of the Pajaro Valley. 
The color is dark brown to black, due to the high per cent of 
humus. 

ORLAND SERIES. These consist of material from the 
former and recent deposits of Stony Creek, in the Colusa area, 
with an admixture of wash from adjacent soils, and occupy the 
lower benches and plains. 

YOLO SERIES. These soils are derived from material 
transported by Cache and Putah creeks in the Woodland area. 
They are deep, silty, and sandy, and generally brown in color. 

OAKDALE SERIES. These are recent soils of old overflow 
channels in the Modesto-Turlock area, with wash from adjacent 



Key to Califobnia Soils 103 

soils. They are brownish in color, micaceous, and underlain by 
lighter subsoil. They occupy a lower position than the Arnold 
along the base of the foothills and on stream bottoms. 

ELDER SERIES. The type soils are found in the Red Bluff 
area, which covers the extreme northern part of the Sacramento 
Valley and its adjacent elevated plains. The soils are derived 
in part from the original deposits of the valley and from modern 
alluvium brought in by the streams that traverse the area. The 
Elder series are dark in color, deep and friable, and occupy the 
alluvial bottoms of the major streams coming from the Coast 
range on the west side of the valley. 

MOCHO SERIES. The type soils are found in the Liver- 
more area lying between the Contra Costa Hills and the Mt. 
Diablo Range. They occupy the bottoms of the valley and are 
still in the process of formation, being purely alluvial. 
ANDERSON SERIES. These consist of reddish, gray, or 
light red soils, occupying upper valley plains and the bottoms of 
intermittent streams. They are usually gravelly, and underlain 
by gravels or compact clay. 

ARBUCKLE SERIES. These are derived mainly from 
coarse conglomerates and slates deposited by streams on upper 
valley floors, and are of comparatively recent origin. They are 
generally of gray color and overlie clay formations. 
MAYWOOD SERIES. The type soils are found in the Red 
Bluff area. They occupy the terraces and alluvial fans of the 
streams on the upper valley floor and are marked by terraces. 
They occur on the west side of the Sacramento Valley, are grayish 
in color, and more friable than the Tehama. 

FRESNO SERIES. These are characterized by prevailing 
light gray color, but are sometimes light red to reddish brown. 
They are generally underlain by subsoils of fine ashy texture, 
light color, and compact close structure, usually separated from 
the overlying soil by an alkali carbonate hardpan of white or 
light gray color. The series is composed of old delta deposits 
formed by shifting streams and mountain torrents, and occuring 
as broad, low, alluvial delta cones. They occupy gently sloping 
plains or slightly rolling valley slopes. The origin is mainly 
granitic, but from volcanic and sedimentary rocks also in part. 

HANFORD SERIES. These are derived from a great vari- 



104 Soils of Califobnia 

ety of rock material deposited as river and delta plains. Some 
even consist of mining debris. They are generally light gray to 
buff in color, but become dark drab, brown, or black in low areas. 
The surface is generally level or slightly sloping, and is frequent- 
ly marked by sloughs or interlacing channels of streams. They 
occupy a lower topographical position than the Fresno series and 
are of more recent origin, and some of the members are subject 
to overflow. They do not have the ashy subsoil or white hard- 
pan of the Fresno series. 

SANTIAGO SERIES. This series is typical in the Santa 
Ana area, where they occur on a delta plain of very recent origin. 
This delta plain was built up by material brought by the Santa Ana 
River and Santiago creek in times of flood, and by an elevation 
of this part of the coast. The river has wandered over this 
delta, covering it with alternating sandy soils, running in lines 
parallel to the ocean. The soils are sandy and occupy some of 
the higher elevations of the delta, and have a subsoil that varies 
from sandy adobe to sandy loam. 

GRIDLEY SERIES. This series in the type region at Marys- 
ville is usually a little higher than the surrounding soils, on land 
that varies from level to slightly rolling. The body of the soils 
are sediments largely reworked by later alluvial agencies. They 
are reddish brown in color, with loam subsoil, and with few ex- 
ceptions are free from hardpan. It is an extensive type in Sut- 
ter County, from the Red Bluff Formation (Pleistocene). 
CORNING, KIRKWOOD, and REDDING series are named 
for type localities in the Red Bluff area. They are 
all derived from the geologic formation known as the Red Bluti 
formation, and have a red color. The Redding series carries 
water-worn gravel, and has a thin heavy subsoil resting on 
hardpan. They are locally known as "Red Lands" and "Hardpan 
Lands." They occupy the higher elevations of the Sacramento 
valley and are gently rolling in character. The Corning series are 
found on the west side of the Valley and are similar to the Red- 
ding series except that the hardpan is absent. The Kirkwood 
series are formed from the washing or erosion of the above 
soils and are deposited on the lower valley plains, on local flats 
and depressions. 

THE CAPAY SERIES of the western part of the Sacramento 
Valley consist of the finer grades of sediment resulting from the 



Key to Califoenia Soils 105 

weathering of complex rocks of the Coast Range mountains and 
deposited over the valley plain, where temporary lakes or pools 
have been formed during periods of heavy rainfall and flood. 
They are characterized by a dark gray color, fineness of texture, 
and are of a heavy plastic character. Owing to the flatness of 
the surface, the drainage is often deficient. 

THE ALVISO CLAY is found near the seacoast, where the 
tides at times cover the land, as at Elkhorn Slough in the Pajaro 
Valley. It is a drab plastic clay, growing pickleweeds, tules, 
saltgrass, etc. 

THE GALVESTON CLAY is found around the waters of 
San Francisco Bay. The surface is flat and only a little above 
mean sea level. It is traversed by open tidal sloughs and rem- 
nants of former drainage channels. It is generally black in 
color at the surface and brown or yellow below. It originates 
from the deposition of clay and the finer silt particles in the slack 
water of the bay and its system of tidal sloughs and marshes. 

SACRAMENTO SERIES. These soils consist of recent 
stream deposits, generally light gray in color, although the siltier 
soils may be darker. They were deposited from shifting river 
currents or from relatively stagnant flood waters covering flood 
plains, and are subject to overflow when not protected by levees. 

FEATHER RIVER SERIES. These occur along the bot- 
toms of the Feather, Bear and Yuba rivers, and are of a deep 
brown color and silty texture. They are subject to overflow and 
the drainage conditions are not very good. 

ALAMO SERIES. These are plains soils of heavy clay loam 
adobe, and clay adobe, dark red to black in color and underlain 
by red hardpan. The surface is low and nearly level and when 
wet is practically a bog. 

SANTA RITA SERIES. The type is found in the Liver- 
more area where the alluvium of the valley has a decided swampy 
character. 

STOCKTON SERIES. These consist in part of alluvium 
and in part of wash from the more elevated soils. The heavier 
members have been greatly modified by weathering and by the 
decomposition of organic matter resulting from swamp or marsh 
conditions. The}^ occupy extensive areas of the lower nearly 
level plains of the Great Valley traversed by minor foothill 



106 Soils of Califobnia 

streams. They are generally older than the Hanford series. The 
lighter members are chocolate color, the heavier members are 
black or dark brown. They are underlain by heavy loams or clay 
loams of lighter color, separated from the soil by a thin white 
calcareous hardpan free from alkali. 

SAN JOAQUIN SERIES. The soils of this series are of a 
prevailing red color, frequently gravelly, both gravel and soil 
particles consisting of well-worn quartzose material. They are 
commonly underlain by red or reddish brown indurated clay or 
sandy layers cemented by iron salts into a fine hardpan. They 
consist of old sediments deposited in the waters or about the 
shores of lakes or bays of early Pleistocene age, modified by 
recent reworking or by alluvial wash. They occupy valley plains 
extending from the lower foothills down to level valley floors 
and margins of present stream channels and are generally exten- 
sive in area. The natural drainage is restricted by deficient 
slope and the underlying hardpan. 

SPECIAL SOILS. Not classified under residual, colluvial 
or alluvial. 

RIVER WASH. The miscellaneous deposits of sand and 
gravel found along rivers and creek beds or spreading over inex- 
tensive flood plains. 

ROUGH STONY LAND. Stony hills or knolls covered by 
rock outcrop and boulders with varying quantities of sand, loam, 
and adobe composing the finer portion. 

MEADOW SOILS. These comprise the low-lying, flat, 
poorly drained land of variable texture and origin. Often ol 
some value for grass or pasture. 

PEAT or MUCK SOILS. These are composed largely of 
organic matter in various conditions of decay. The muck is an 
advanced state of change of the peat. 

SANDHILL, DUNESAND, and COASTAL BEACH SOILS 

are deep sands, often of little agricultural value. 

LAKE and MARSH SOILS, such as those of Butte Valley 
in the north end of the state, are formed by the drying up of 
former lakes in an enclosed basin. The soils are loamy and too 
wet for tillage, and often mucky or peaty. They are valuable 
where drainage is possible. 



Key to Califobnia Soils 107 

TABLE OF CALIFORNIA SOIL CLASSES. The follow- 
ing table of the physical analyses of the various classes of Cali- 
fornia soils is only tentative and subject to modification as new 
classes are formed. It gives the average composition of the soils 
so far as the work has been carried to date. As the work of 
mapping the soils is extended, these averages will be changed to 
some extent, and are therefore not fixed and final. They illus- 
trate the differences in composition in a general way. 

AVERAGE COMPOSITION OF CALIFORNIA SOILS 

Very 
Fine Coarse Medium Fine fine 

gravel sand sand sand sand Silt Clay 

Clay 0.4 1.1 1.2 4.5 8.2 4a.l 44.1 

Clay adobe 0.6 2.2 2.1 6.8 9.4 39.3 39.4 

Silty clay adobe 1.1 1.7 1.6 4.0 6.0 52.1 33.4 

Silty clay 0.2 0.4 0.5 3.4 3.4 59.6 32.1 

Clay loam 0.5 1.5 1.5 9.5 19.7 41.9 26.7 

Gravelly clay 

loam 6.6 10.7 6.9 14.4 9.4 26.1 25.6 

Silty clay loam.. 0.1 0.5 0.6 4.4 10.6 60.3 23.0 

Loam adobes ... 2.4 6.1 4.1 14.7 19.5 28.9 22.8 

Stony loam 4.6 7.6 4.9 13.1 15.4 31.2 22.7 

Stony clay loam 1.6 5.6 4.5 8.5 17.6 39.4 22.5 

Clay loam adobe 1.0 3.2 2.8 9.4 13.2 38.5 21.8 

Silt loam 0.3 1.4 1.3 6.8 11.2 60.4 19.3 

Loam 0.2 3.9 4.4 17.3 16.7 39.7 17.9 

Sandy adobe 1.3 3.9 6.4 16.9 18.9 34.4 17.0 

Gravelly loam .. 5.7 9.9 6.8 17.4 11.3 32.8 14.8 
Gravelly fine sandy 

loam 2.5 6.1 6.8 27.0 21.7 22.7 12.9 

Stony sandy loam 7.4 14.7 7.9 11.7 16.9 28.9 12.3 
Gravelly sandy 

loam 8.9 13.2 8.1 16.3 13.3 29.3 10.5 

Fine sandy loam 1.0 3.2 4.6 23.4 26.6 28.7 10.4 

Sandy loam 3.7 16.1 12.9 24.7 12.5 23.7 10.2 

Silty fine sandy 

loam 0.0 0.2 0.5 14.6 32.8 41.9 9.9 

Gravelly sand ..25.6 17.8 8.8 14.3 8.8 13.2 8.6 
Coarse sandy 

loam 9.8 29.4 10.7 17.7 6.0 18.3 7.5 

Coarse sand 10.9 28.0 16.7 21.4 6.6 7.8 5.1 

Loamy coarse 

sand 8.1 22.3 12.7 21.7 25.8 5.6 3.8 

Fine sand 0.4 2.8 4.7 39.3 31.5 16.4 3.8 

Sand 1.5 12.7 23.6 37.8 12.6 7.6 3.7 

Dune sand 0.0 24.7 46.3 25.2 0.8 1.7 1.6 



CHAPTER XV 
CALIFORNIA SOILS DESCRIBED BY CLASSES 

CLAY SOILS. ADOBE SOILS 

In the following general description of the soils arranged by 
classes, the average physical analysis of each soil is given in the class 
to vi^hich it belongs. At the foot of each table is given the highest, 
lowest, and average amount of fine gravel, coarse sand, medium sand, 
fine sand, very fine sand, silt and clay in the soils described. 

A careful study of the table will therefore show wherein each 
soil is modified by local conditions, such as the nature of the subsoil, 
concerned. These affect the general properties of the soil and show 
whether it is light or heavy, easy or difficult to drain and cultivate, or 
whether it is plastic, puddles, etc. The local productiveness of each 
soil is modified by local conditions, uch as the nature of the sub-soil, 
where the soil occurs, local topography, climate, etc. The conditions 
are given in broad outline with each soil and the reader is referred to 
the annual reports of the U. S. Bureau of Soils for extended local 
details. 

Under the present system of classification the commercial value 
of the soils can be seen in the field in the character of the soil and 
from its relation to natural vegetation and artificial crops. It can be 
mapped independently of a knowledge of the geology of the region, 
or of the exact chemical and physical character of the soil. It is now 
possible to map in the field the areas and distribution of the types, 
leaving the work of geologic origin, and minute differences to be 
noted by the soil chemist and physicist in their laboratory investiga- 
tions . The object of a soil survey, whether of an acre or of a county, 
is to provide an accurate basis for the adaptation of soils to crops. 

CORRELATION. The soils of different areas having the same tex- 
ture and composition, and the same crop value (the local climatic 
variations being considered), are given the same name, no matter 
what part of the state they occur in. This simplifies the nomenclature 
and calls attention to the similarities of soils and to the possibilities 
of extending industries into new localities. While no attempt is made 
as yet by the Government to correlate the soils of the different states 
except in a very general way, certain close similarities are recognized 
by all: and soil names are carried across the boundaries of a state 
in adjoining states. The Fresno sand is the equivalent of the Colo- 
rado sand in the lower Arkansas Valley and corresponds very closely 
in texture and crop value to the truck soils of the Atlantic Coast. 
The Fresno fine sand is the equivalent of the Laurel fine sand of 
Colorado; the Fresno fine sandy loam, to the Marshall silt loam of 
Colorado and to the Weber fine sandy loam of Utah; the Maricopa 



California Soils Described by Classes 109 

gravelly loam, to the Bingham gravelly loam of Utah and the Bridger 
gravelly loam of Oregon; and the Maricopa sandy loam is the equiv- 
alent of the Bridger loam of Oregon, etc. 

CHANGES IN NAMES. The U. S. Bureau of Soils with increased 
knowledge of soils gained as the surveys progress have found it nec- 
essary to make certain readjustments in the classifications and names. 
Some of the names that appeared on the soil maps when published 
were provisional only, awaiting investigation and comparison. These 
changes in names have been carefully noted to date in each soil 
description, and should be noted on the government maps where 
persons have copies. 

CLAY 
Fine Coarse Medium Fine Very 
gravel sand sand sand fine sand Silt Clay 

Alvlso 0.0 0.4 0.7 2.3 0.4 52.3 44.5 

Dunnig-an 0.1 0.5 0.6 2.3 1.1 30.8 64.5 

Esparto 0.0 0.3 0.9 5.9 7.6 43.4 41.6 

Galveston 0.6 2.0 2.1 6.4 12.1 31.5 45.2 

Imperial 0.1 0.5 0.6 3.5 6.3 36.7 49.1 

Livermore 0.3 0.8 1.1 6.5 16.3 44.5 30.4 

Sacramento 0.0 0.5 0.7 3.4 1.8 41.0 52.7 

Sutter 1.1 4.6 4.3 9.9 11.2 29.6 39.2 

Tehama 2.1 2.0 1.8 4.9 18.5 34.9 35.5 

Yolo 0.0 0.1 0.1 0.9 7.6 50.9 40.4 

Willows 0.5 0.4 0.6 3.2 7.4 45.1 43.4 

Highest 2.1 4.6 4.3 9.9 18.5 52.3 64.5 

Lowest 0.0 0.1 0.1 0.9 1.1 29.6 34.4 

Average 0.4 1.1 1.2 4.5 8.2 40.1 44.1 

Soils that contain over 50 per cent of silt and clay together are 
called clay soil if the clay content is over 30 per cent. They vary 
widely according to the rocks of the drainage district in which they 
occur, and in the iron and organic matter present. They are the 
reverse of the sand soils in character, admitting air and water slowly. 
Heavy, compact and silty, they become plastic and sticky when wet, 
with a tendency to puddle, and are retentive of moisture. This makes 
them cold and hard to till. They dry slowly, forming a hard crust, 
lumps and clods, and crack badly, and are hard on plant roots. The 
natural drinage is generally deficient on account of the low positions 
occupied by the soils. On the other hand these soils are rich in plant 
food, and under-drainage removes excess of moisture and promotes 
aeration and warmth. There is a point between wetness and dryness 
where clay soils crumble quite readily and are friable when carefully 
handled, and they should be tilled only at such a time as far as pos- 
sible. They sufifer from the extremes of both wet and dry weather 
and are expensive to cultivate. Clay is an extremely fine soft powder 
produced by the chemical as well as mechanical decomposition ot 
various minerals. It consists of particles from 0.005 to 0.000 milli- 
meters in diameter. When wet, clay swells up into a sticky plastic 
substance which shrinks in drying to a tough coherent mass. It is 
very retentive of water, gases, and minerals in solution, and presents 
such a large surface for the plant rootlets to feed on that the clay 
soils are sometimes called strong soils by the farmer. Clay also acts 
as a cement which holds the other ingredients together and renders 



110 Soils of California 

the soil hard to till. Silicate of alumina is always present in large 
quantities and serves to flocculate the soil particles. Without clay the 
sand would collapse into close packed grains as soon as it became 
dry, and loose tilth would be impossible. 

ALVISO CLAY. Mapped in the Pajaro area. Drab, six feet deep. 
OCCURS on tidal flats. ORIGIN: alluvial. CROPS: Crops of 
barley have been grown where protected by levees and washed with 
fresh water. 

DUNNIGAN CLAY. Mapped in the Woodland area. Yellow to dark 
gray or black, three feet deep. SUBSOIL: Yellow or brown clay. 
OCCURS on long, narrow areas, in depressed or low flat areas. Lo- 
cally called "Hogwallow land" in Yolo and Colusa districts. ORIGIN: 
Fine wash from the flood waters of the basin and wash from higher 
soils. CROPS: Unfit for cultivated crops without underdrainage. 
Generally alkaline. 

CAPAY CLAY. Mapped in the Woodland area. No analysis re- 
ported, gray to gray brown, sometimes tinged with red, three feet 
deep. SUBSOIL: Dense reddish to yellowish brown clav. OCCURS 
on low ground, flat, broken by sloughs and creeks. ORIGIN: Recent 
alluvial. CROPS: Grain, hay, alfalfa where well drained; alkali 
where the drainage is imperfect. 

ESPARTO CLAY. Mapped in the Woodland area. Yellow to dark 
brown, two to three feet, drainage generally good. SUBSOIL: 
Clay or clay loam. OCCURS on broad slopes approaching the hills; 
flat to easy slopes. ORIGIN: Recent alluvial. CROPS: Dry farmed 
to grain, alfalfa, general farm crops, sugar beets; adapted to sor- 
ghum, Egyptian corn, peaches, apricots, almonds, figs, grapes. 
GALVESTON CLAY. Mapped in the Los Angeles and San Jose 
area. Black to brownish gray, over six feet deep, often saturated 
-'•ith salt water. SUBSOIL: Blue or black mud, gray or bluish 
gray silt. OCCURS around San Francisco Bay, on the coast in 
coastal swamps, in river channels. ORIGIN: Product of lacustrine 
or swamp deposits derived from the slack waters of tidal flats, 
sloughs and estuaries, and silt deposited by rivers in flood times, 
combined with swamp vegetation. CROPS: Owing to the presence 
of large amount of alkali salts it has no agricultural value under 
present conditions of drainage. 

IMPERIAL CLAY. Mapped in the Imperial and Indio areas. Slate 
colored, micaceous, six feet. SUBSOIL: A mixture of clay silt and 
fine sand. OCCL^RS in low level places, sometimes hummocky. 
ORIGIN: Mixed sediments from mountains and rivers. CROPS: 
Too strong in alkali except for the most alkaline resistant crops, 
such as sorghum, barley, Egyptian cotton, rice. 

LIVERMORE CLAY. Mapped in the Livcrmore area. Dark 
chocolate brown, thirty to thirty-six inches. SUBSOIL: Gray brown 
Hay loam. OCCURS on valley bottoms, poorly drained. ORIGIN: 
Colluvial and alluvial. VEGETATION: Valley oak. CROPS: Hay, 
grain. 

SACRAMENTO CLAY. Mapped in the Marysville area. Black, six 
feet deep. Locally called "Tulc Land," water logged. SUBSOIL: 
Clays or hardpan. OCCURS in slough basins, overflowed areas, 



Cazifoenia Soils Described by Classes 



111 



rarely free from standing water. ORIGIN: From material carried 
in suspension by river flood waters, with annual additions. CROPS: 
Too expensive and unprofitable to drain under present methods. Often 
alkaline. 

SACRAMENTO HEAVY CLAY. Mapped in the Woodland area. 
Blue black to drab, six feet, high per cent of organic matter. SUB- 
SOIL: Similar. OCCURS on floor of basins; flat with slight slope. 
ORIGIN: Wash from higher soil bodies. CROPS: Grain; where 
protected from overflow adapted to grain, sorghum, Egyptian corn, 
hay and other forage crops. 

SUTTER CLAY. Mapped in the Marysville area. Brown, few inches 
deep. SUBSOIL: Sticky, yellowish clay. ORIGIN: Material washed 
from the Marysville Buttes; from the finer material from the 
weathering of volcanic rocks. CROPS: Grain in wet years. 
TEHA.MA CLAY. Mapped in the Red BluflF area. Gray brown to 
yellowish brown; adobe-like when wet; when dry is hard and cracks 
and checks; thirty-six to forty-eight inches. SUBSOIL: Variable. 
OCCURS from gently rolling to flat and depressed areas. ORIGIN: 
Wash from higher lying soils. CROPS: Grazing. 

YOLO CLAY. Mapped in the Woodland area. Brown, six feet deep, 
lacks organic matter. SUBSOIL: Lighter color, silty clay. OCCURS 
in irregular bodies; gently sloping from streams; low flat areas 
ORIGIN: Alluvial. CROPS: Barley, alfalfa; adapted to tree fruits, 
grapes, beets and other field crops. 

WILLOWS CLAY. Mapped in the Colusa and Woodland areas. 
Reddish, yellowish yellowish brown to drab; three to six feet deep; 
drainage poor. SUBSOIL: Clay, hardpan. OCCURS on nearly 
level valley plains, depressions, drainage troughs. ORIGIN: Allu- 
vial. CROPS: Grazing. Generally alkaline. 

CLAY ADOBES very 

Fine Coarse Medium Fine fine 

gravel sand sand sand sand Silt Clay 

Alamo 0.2 3.4 4.2 10.4 8.3 51.9 21.9 

Altmont 0.1 0.9 1.4 4.9 10.4 48.1 34 1 

Arnold 0.1 2.1 2.3 10.5 4.9 37.4 42 5 

Capay 0.2 1.8 2.3 10.9 16.9 44.5 23.2 

Daulton 2.0 4.5 2.8 6.7 6.1 25.3 52.7 

Diablo 0.3 1.2 1.6 8.4 19.1 38.5 31.0 

Dublin 0.1 0.6 0.8 5.6 17.6 30.1 45.0 

Hanford 0.5 2.6 2.5 8.5 8.3 41.5 35.8 

Media 2.3 7.1 4.8 10.2 10.3 34.7 30.6 

Norman 0.4 1.2 1.1 2.8 0.9 55.6 37.4 

Pleasanton 1.5 4.5 3.6 10.4 18.6 28.3 33 2 

Portersville .... 1.3 5.0 3.2 5.7 6.7 34.4 43.5 

Sacramento 0.0 0.4 0.3 4.0 3.0 46.9 46 3 

Salinas gray .... 1.1 3.6 4.0 10.3 10.6 37.9 30 7 

San Joaquin .... 0.5 2.4 1.8 10.4 11.7 32.0 41 4 

Santa Rita 0.0 0.1 0.5 1.9 12.3 43 9 413 

Sites 0.0 0.8 1.8 5.3 5.9 37.2 49 

Stockton 0.5 1.0 0.8 4.0 7.8 37.5 48 5 

Vallecitos 0.0 0.5 0.5 3.7 21.9 37.8 35 6 

Vina 1.5 2.6 2.2 4.3 9.0 33.3 46.9 

Willows 0.1 1.2 0.8 3.9 4.7 37.7 55.7 

Highest 2,3 7.1 4.8 10.9 21.9 55.6 55 7 

Lowest 0.0 0.1 0.3 1.9 0.9 25.3 219 

Average 0.6 2.2 2.1 6.8 9.4 39.3 39.4 



112 Soils op Califobnia 

The Mexican "adobe" is an unburnt brick dried in the sun, and 
in common use in all western regions where the rainfall is small, 
the name being derived from the Spanish "adobar," meaning to "daub 
or plaster." The term was naturally applied to the clayey soils 
suitable for making the "bricks without straw" or burning. All the 
adobe soils are clay soils that have typical qualities, as shown by a 
peculiar stickiness, or adhesiveness, when wet, and checking into 
cubes when dry. 

COMMON PROPERTIES: The table shows that they contain from 
22 to 36 per cent of clay and 25 to 56 per cent of silt. That is, over 
80 per cent of their material consists of the Hnest particles of which 
soils are composed. This makes them dense, close and compact; 
slow to absorb water, but retain water tenaciously; impervious to 
more water when thoroughly wet; plastic, sticky, or waxy; puddling 
when wet; tough, heavy and putty-like, and hard to cultivate. They 
dry out slowly, baking on exposure, and become hard and compact 
when dry. They expand when wet, and shrink while drying, causing 
the soil to check and crack. When the sand contents are above 
normal, and when they are well drained, they become fairly friable. 
They are generally dark gray in color, with occasional brown 
grays and black, and occur in irregular bodies at the base of foot- 
hills, on low level plains, and in narrow valleys, or in river depres- 
sions that are subject to overflow. Most of them are used only for 
grazing, hay or grain, but with irrigation, drainage and thorough 
cultivation, are adapted to alfalfa, grain and general farm crops, 
and locally to vines and fruit trees. 

ALAMO CLAY ADOBE. Mapped in the Marysville area. Gray 
to black, two to three feet deep. SUBSOIL: Red hardpan. OCCURS: 
Low, subject to overflow. ORIGIN: Sedimentary and alluvial. Pleis- 
tocene lake deposits altered and added to by wash from higher land. 
CROPS: Grazing, hay, grain, some grapes and fruits. 

ALTAMONT CLAY ADOBE. Mapped in the Livermore area. 
Brown to chocolate, three to five feet, sticky when wet but dries 
loose and friable. SUBSOIL: Yellow brown clay loam. OCCURS 
on high hills. ORIGIN: Residual, from Tertiary sandstones and 
shales. CROPS: Grain and hay. 

ARNOLD CLAY ADOBE. Mapped in the Modesto-Turlock area. 
Purplish brown, black to dark gray, fifteen inches to three feet deep. 
OCCURS on level plains, and covering hillsides. ORIGIN: Lacus- 
trine, and alluvial weathering of andesitic tuf¥. CROPS: Dry farming 
and pasture. 

CAPAY CLAY ADOBE. Mapped in the Woodland area. Gray to 
dark brown, three feet deep, variable in texture. SUBSOIL: Clay, 
yellow to reddish brown. OCCURS: Flat, low levels of the plains. 
CROPS: Grain and hay. Frequently alkaline. 

DAULTON CLAY ADOBE. Mapped in the Madera area. Red, 
six feet. SUBSOIL: Granitic and quartz rocks. ORIGIN: Residual. 
CROPS: Grain. 

DIABLO CLAY ADOBE. Mapped in the Livermore area. Dark 
brown or gray to black, contains an excess of lime, twenty-four to 



Califobnia Soils Descbibed by Classes 113 

forty inches. SUBSOIL: Bedrock. OCCURS on the Diablo hills 
and foothills. Fossil oyster shells (Astiga titan) are often found on 
some of the peaks and ridges. ORIGIN: Residual, modified by col- 
luvial from the Tertiary limestones and calcareous sandstones and 
shales. Small amount of alkali. CROPS: Dry farmed to hay and 
grain. 

DUBLIN CLAY ADOBE. Mapped in the Livermore area. Slate 
to black color, twelve to fifteen inches deep. SUBSOIL: Black clay. 
OCCURS on valley bottoms, nearly level, poorly drained. ORIGIN: 
Colluvial wrash from hills. CROPS: Dry farmed to hay and grain. 

HANFORD CLAY ADOBE. Mapped in the Sacramento area as 
Salinas gray adobe. Dark gray to nearly black, considerable fine to 
coarse sand. SUBSOIL: Sand, clay, volcanic mud flows. OCCURS 
as irregular bodies, base of foothills, upper valley margins, flat 
topped tablelands. ORIGIN: From the weathering and breaking 
down of interstratified beds of Pleistocene clay, ash and volcanic 
muds, modified by stream wash. CROPS: Grazing, grain, hay. 
VALLEY PHASES: Three feet deep, gray to black silt. SUBSOIL: 
Sandy adobe or hardpan, in local depressions and sinks. 
MEDIA CLAY ADOBE. Mapped in the Madera area. Red, three 
to six feet. SUBSOIL: Partially decomposed granitic rock. OCCURS 
on rolling lands. ORIGIN: Colluvial and alluvial. CROPS: Grazing. 
NORMAN CLAY ADOBE. Mapped in the Colusa area. Dark 
brown to black: moderately friable when moisture conditions are 
favorable. SUBSOIL: Clay, clay loam, yellowish to bluish. OCCURS 
in minor depressions of gently sloping valley plains; in narrow 
valleys in foothills in irregular bodies. ORIGIN: Alluvial from the 
sediments of intermittent streams, and wash of more elevated soils. 
CROPS: With irrigation, drainage and thorough cultivation, alfalfa, 
grain and general farm crops. 

PLEASANTON CLAY ADOBE. Mapped in the Livermore area. 
Dark brown, carries angular gravel, eighteen to thirty-six inches. 
SL^BSOIL: Red yellow clav. OCCURS on hills and narrow ridges. 
ORIGIN: Sedimentary. CROPS: Grazing, hay. 

PORTERSVILLE CLAY ADOBE. Mapped in the Portersyille 
and Madera areas. Black, six feet deep, small rock fragments, lime 
concretions, locally called "dry bog land," high per cent of organic 
matter. SUBSOIL: Similar. OCCURS at lower elevations than 
the Portersville clay loam adobe. ORIGIN: Largely colluvial, wash 
from the higher slopes. CROPS: Dry farming to grain. Little 
alkali. 

SACRAMENTO CLAY ADOBE. Mapped in the Woodland area. 
Gray to black, two to three feet deep, poorly drained. SUBSOIL: 
Dark brown, j'ellow brown clay. OCCURS on low overflowed flat 
areas. ORIGIN: Alluvial. CROPS: Pasture and grain. 
SALINAS GRAY ADOBE. Mapped in the San Jose and lower 
Salinas Valley areas. That mapped as Salinas gray adobe in the 
San Bernardino and Sacramento areas has been reclassified as Han- 
ford clay adobe. Light to dray gray, nearly black, texture variable, 
one to six feet deep; drainage fair, well supplied with organic matter. 



114 Soils of California 

SUBSOIL: Sandy loam, clay loam, hardpan, disintegrated granite. 
OCCURS on smooth or slightly sloping land, on higher elevations, 
foothills, in narrow irregular bodies. ORIGIN: Wash from granite 
hills and shaly sandstones, from Jurassic formations, primarily 
residual. CROPS: Grain, alfalfa, barley in the lower Salinas Valley; 
peaches, prunes, grapes at San Jose. Some alkali where poorly 
drained. 

SAN JOAQUIN CLAY ADOBE. Mapped in the Portersville area. 
Dark red, eighteen inches to six feet. SUBSOIL: Dense red hardpan. 
OCCURS in low depressions, hog wallow depressions, no drainage. 
ORIGIN: Lacustrine of Pleistocene age. CROPS: Grazing and dry 
farming. 

SANTA RITA CLAY ADOBE. Mapped in the Livermore area. 
Dark gray, never puddles but checks to a friable surface easily culti- 
vated, three to six feet. SUBSOIL: Slaty to black heavy clay. 
OCCURS on flat, poorly drained land, some hog wallows. ORIGIN: 
On site of a former shallow lake, then a tule swamp. Alkali variable. 
CROPS: Hay, grain, sugar beets. 

SITES CLAY ADOBE. Mapped in the Woodland area. Red brown 
to gray, eighteen inches to three feet. SUBSOIL: Red clay, white 
or green calcareous clay, clay loam. OCCURS on rolling, hilly 
land; steep, dissected by narrow valleys. ORIGIN: Residual and col- 
luvial. CROPS: Pasture, grain, hay. 

STOCKTON CLAY ADOBE. Mapped in the Marysville, Modesto- 
Turlock and Stockton areas. Chocolate browns to blacks, one to 
five feet deep, drainage deficient. SUBSOIL: Light yellow silty 
clay. OCCURS in irregular shaped bodies in low level places. 
ORIGIN: From a great variety of rocks, modified by ancient Pleis- 
tocene sediments. CROPS: Alfalfa, grain, forage, vines, fruit trees. 
Generally free from alkali. 

VALLECITOS CLAY ADOBE. Mapped in the Livermore area. 
Red brown, thirty to thirty-six inches. SUBSOIL: Yellow brown 
clay. OCCUR.S on narow ridges and in deep ravines. ORIGIN: 
Residual, from metamorphic rocks. CROPS: Grazing, hay, grain. 
VINA CLAY ADOBE. Mapped in the Red Bluf¥ area. Brown, pud- 
dles but friable with tillage, two to six feet. SUBSOIL: Clay loam. 
OCCURS in broad tracts below terraces; level, overflowed, drainage 
sluggish. ORIGIN: Alluvial. VEGETATION: Valley oaks, wild 
oats. CROPS: Grain, adapted to stone fruits. 

WILLOWS CLAY ADOBE. Mapped in the Colusa and Woodland 
areas. Dark chocolate brown, three feet deep, drainage poor. SUB- 
SOIL lighter in texture. OCCURS in irregular shaped, elongated 
bodies, occupies draws and depressions in valley plains. ORIGIN: 
Wash from foothills and from other soils. CROPS: Dry farming. 
When drained, adapted to sugar beets, alfalfa and general farm crops. 
Apt to be alkaline. 

SILTY CLAY ADOBE 

KIRKWOOD SILTY CLAY ADOBE. Mapped in the Red BluflF 
area. Dark gray to black, smooth texture, very sticky, six feet and 
over. SUBSOIL: Same, lighter textured. OCCURS on level or 



Califobnia Soils Described by Classes 115 

gently sloping plains. ORIGIN: Wash from the Red Bluff formation 
and from adjacent soils. Not extensive or important. CROP: Dry 
farmed to grain. P'ine gravel, 1.1; coarse sand, 1.7; medium sand, 1.6; 
fine sand, 4.0; very fine sand, 6.0; silt, 52.1; clay, 33.4. This soil, as 
the name shows, is a clay adobe containing an excess of silt. 



CHAPTER XVI 

SILTY CLAY. 

SILTY CLAYS. CLAY LOAMS. GRAVELLY CLAY 

LOAMS. CLAY LOAM ADOBES. SILTY 

CLAY LOAMS. LOAM ADOBES. 

STONY CLAY LOAMS. 

Very 
Fine Coarse Medium Fine fine 

gravel sand sand sand sand Silt Clay 

Pajaro 0.0 0.3 0.6 2.4 1.5 65.3 29.0 

Sacramento 0.5 0.9 0.7 4.7 3.8 55.2 33.6 

Yolo 0.0 0.1 0.1 3.2 5.0 58.3 33.5 

Average 0.2 0.4 0.5 3.4 3.4 59.6 32.1 

The silty clays are between the silt loams and the clays in 
character, there being about the same amount of silt and more clay 
than in the silt loams, and less of the fine sands. They are smooth 
and vary from light to heavy texture. Being compact, they puddle 
when wet and bake and check on drying. When well drained and 
well cultivated, they break into a friable loam and become mellow. 
They are easily cultivated if worked at the most favorable time so 
far as their moisture contents are concerned. 

PAJARO SILTY CLAY. Mapped in the Pajaro area. Light yellow 
or drab, high per cent of humus; twelve to thirty-six inches. SUB- 
SOIL: Dark loam, silt loam. OCCURS in old channels, in low 
depressions, in river bottoms. ORIGIN: From weathered shales 
deposited by flood waters of streams. CROPS: Adapted to many 
farm crops; wheat, barley, sugar beets, beans. 

SACRAMENTO SILTY CLAY. Mapped in the Colusa and Wood- 
land areas. Black to dark gray; six feet. SUBSOIL: Light colored 
silty and sandy sediments, heavy clay adobe. OCCURS in irregular, 
elongated bodies, nearly level. ORIGIN: Old stream flood plains 
sediments, mixed with wash from adjacent soils. CROPS: Dry 
farming and grain, wheat, barley; with artificial drainage and inten- 
sive cultivation, adapted to sorghum, broom corn, Egyptian corn, 
alfalfa and sugar beets Sometimes alkali is found in the large 
depressions. 

YOLO SILTY CLAY. Mapped in the Woodland area. Chocolate 
brown, good drainage, three to six feet. SUBSOIL: Brown clay 
loam, clay. OCCURS: Flat or slightly undulating along creek 
courses. ORIGIN: Alluvial. CROPS: Grain, alfalfa, wine and 
raisin grapes; adapted to sugar beets, sorghum, Egyptian corn, 
vegetables, etc. 



SiLTT Clay 117 

CLAY LOAMS 

Very- 
Fine Coarse Medium Fine fine 
gravel sand sand sand sand Silt Clay 

Arbuckle 1.6 3.4 2.9 9.2 11.3 45.9 25.8 

Capay 0.2 1.8 2.3 10.9 16.9 44.5 23.2 

Daulton 1.5 1.9 1.9 11.3 34.0 24.3 25.2 

Dublin 1.3 2.4 1.7 11.6 10.7 47.7 24.4 

Esparto 0.0 1.1 3.1 12.7 11.4 40.8 30.3 

Fresno 0.4 2.3 2.5 8.0 22.1 40.4 24.2 

Gila 0.0 0.6 1.1 6.0 11.9 42.2 37.5 

Hanford 0.2 0.7 0.5 6.9 18.1 46.3 27.0 

Imperial 0.2 0.2 0.2 3.2 7.6 48.1 35.7 

Lewis 0.7 2.3 1.9 8.3 14.4 49.8 22.3 

Livermore 0.4 1.5 1.6 9.9 21.8 41.1 23.T 

Madera 0.8 4.5 3.7 10.1 11.7 40.6 28.2 

Marcuse 0.2 3.0 3.5 14.4 14.5 41.3 23.1 

Oxnard 0.3 1.0 1.1 13.9 18.7 36.9 21.7 

Placentia 0.2 0.7 0.6 4.1 21.6 43.9 28.8 

Sacramento 0.3 0.8 0.5 2.5 6.3 40.3 49.7 

San Joaquin 1.9 4.9 3.6 10.7 24.6 29.1 25.2 

Sierra 2.7 6.1 3.3 9.0 8.1 41.0 24.1 

Stockton 0.1 1.4 1.3 12.1 14.5 48.3 21.8 

Tassajero 0.0 0.2 0.9 10.4 28.8 33.3 26.4 

Vina 0.4 1.0 1.4 7.3 22.3 47.9 19.2 

Willows 0.0 0.5 0.8 9.3 15.0 47.4 26.9 

Yolo 0.0 1.9 3.9 16.6 16.6 42.1 19.0 

Highest 2.7 6.1 3.9 16.6 34.0 49.8 49.7 

Lowest 0.0 0.2 0.2 2.5 7.6 24.3 19.0 

Average 0.5 1.5 1.5 9.5 19.7 41.9 26.7 

Soils containing 50 per cent of silt and clay are called clay loams, 
if they contain from 20 to 30 per cent of clay, or less than SO per 
cent of silt. The average of the analyses show that the California 
clay loams contain about 42 per cent of silt and 27 of clay, with 
nearly 20 per cent of very fine sand and 10 of fine sand. They are 
rather heavy, being a little heavier than silt loam but not so heavy 
or sticky as adobe, yet stiff and compact. They do not crack w^hen 
dry in the manner true adobe does. They readily absorb and retain 
water and are sticky and tenacious when wet. The clay loams require 
very heavy farm equipment, the cultivation being limited to a some- 
what narrow range of moisture conditions. On the other hand, they 
are friable and mellow and easily cultivated under favorable moisture 
upon local conditions of drainage, climate and careful management, 
conditions such as when well drained. They arc apt to contain 
alkali in spots, especially in low poorly drained areas, and are to be 
feared on this account more than the other loams. The crop depends 

ALTAMONT CLAY LOAM. Mapped in the Livermore area. Dark 
brown, carries fragments of shale, 18 to 30 inches. SUBSOIL: Yel- 
low clay loam. OCCURS on steep hills. ORIGIN: Residual from 
shales. VEGETATION: Live oak, poison oak, maple, shrubs. 
CROPS: Grazing, hay, grain. 

ARBUCKLE CLAY LOAM. Mapped in the Woodland area. Brown 
or gray brown; 24 to 36 inches deep, small percent of gravel; drain- 
age variable. SUBSOIL: Yellowish brown clay loam; clay. OC- 
CURS in large irregular bodies, on flat to gentle slopes. ORIGIN: 
from the deposits of finer material carried by the foothill streams, 



118 Soils of Califobnia 

modified by later wash from the more elevated surrounding soil 
bodies. CROPS: Wheat, barley, wine and raisin grapes; hardy iruits; 
general farm crops; dairy farming. 

CAPAY CLAY LOAM. Mapped in the Woodland area. Gray to 
brown, six feet deep, contains tine gravel, well drained. SUBSOIL: 
Heavy, red brown clay. OCCURS along small intermittent 
streams. ORIGIN: Recent alluvial. CROPS: Grain, almonds, grapes. 
Free from alkali where well drained. 

DAULTON CLAY LOAM. Mapped in the Madera area. Brown, 
two to six feet. SUBSOIL: Quartz, schist, granitic rocks. OCCURS 
on rolling foothills. ORIGIN: residual. CROP: Grain. 
DUBLIN CLAY LOAM. Mapped in the Livermore area, Brown to 
black, one to four feet. SUBSOIL: Loam. OCCURS on slopes at the 
foot of hills. ORIGIN: Colluvial and alluvial. CROPS: Dry farmed 
to grain; irrigated — peaches, pears, prunes. 

ESPARTO CLAY LOAM. Mapped in the Woodland area. Yellow 
to yellow brown; three feet deep. SUBSOIL: Silty clay; clay loam. 
OCCURS: Marks the position of present or former streams; on nar- 
row or of expansive ridges, slightly elevated above the surrounding 
level. ORIGIN: Recent alluvial. CROPS: Grain, alfalfa, apricots, 
peaches, figs, almonds, grapes; adapted to beans, beets and general 
farm crops. Free from alkali. 

FRESNO CLAY LOAM. Mapped in the Madera area. Brown to 
black, two to six feet. SUBSOIL: Bluish hardpan. OCCURS: Level, 
marked by sloughs, drainage poor. ORIGIN: Alluvial. Carries some 
alkali. CROPS: Local — alfalfa, prunes, plums, pears. 
GILA CLAY LOAM. Mapped as Imperial loam in the Yuma 
California area. Chocolate brown, three to six feet deep; contains 
considerable organic matter. SUBSOIL: Sand, clay. OCCURS: Gen- 
erally level, in bottom lands, above overflow and quite well drained. 
ORIGIN: Deposited directly from river waters. CROPS: Under 
careful management should prove valuable for cereals, and such sum- 
mer annuals as Kafifir, Egyptian, and Indian corn, millet, sorghum and 
all crops not requiring intertillage. Contains from 0.2 to more than 
3 per cent alkali, hence more to be feared than others of the series. 

HANFORD CLAY LOAM. Mapped in the Madera area. Mapped 
as Santiago silt lo?m in the San Bernardino and San Gabriel areas; 
and as Oxnard silt loam in the BakersField area. Chocolate brown 
to black; contains high per cent of organic matter, three to six feet 
deep. SUBSOIL: Sand, fine sandy loam. OCCURS: Level, low flat 
tracts cut by sloughs and remnants of former stream channels. ORI- 
GIN: Alluvial. CROPS: Alfalfa, grain, small fruits. Generally free 
from injurious quantities of alkali. , 

IMPERIAL CLAY LOAM. Mapped as Imperial loam in the Im- 
perial area. Reddish, contains considerable organic matter. SUB- 
SOIL: Clay loam; clay. OCCURS: Smooth and level. ORIGIN: 
River sediments deposited while the area was submerged, or from 
overflow waters. CROPS: Adapted to wheat, barley, sugar beets, 
Kaflir corn, Egyptian corn, sorghum, alfalfa if not pastured. Gen- 
erally some alkali, heavy in spots. 



SiLTY Clay 119 

LEWIS CLAY LOAM. Mapped in the Portersville area. Grayish, 
six feet deep; poorly drained. SUBSOIL: Gravel, hardpan. OCCURS 
in long narrow strips, uneven, lowland. ORIGIN: Alluvial, hne sedi- 
ments deposited by creeks in body of quiet water. CROPS: Graz- 
ing only. Alkali always present. 

LIVERMORE CLAY LOAM. Mapped in the Livermore area. 
Gray brown, bakes, checks, three to four feet. SUBSOIL: Yellow 
brown clay loam. OCCURS: Level, well drained. ORIGIN: Colluvial 
and alluvial. VEGETATION: Valley oak. CROP: Grain, grass. 
MADERA CLAY LOAM. Mapped in the Madera area. Brown, three 
to six feet. SUBSOIL: Red hardpan. OCCURS along the smaller 
stream courses. ORIGIN: Colluvial and alluvial. CROPS: Grain, 
adapted to fruit locally. 

MARCUSE CLAY LOAM. Mapped in the Marysville area: Gray 
to black, two to three feet deep. SUBSOIL: Reddish, sticky loam. 
ORIGIN: Alluvial, deposited by overflow waters. CROPS: Grazing 
during dry season. Alkali generally present in dangerous quantities. 
OXNARD CLAY LOAM. Mapped as Oxnard loam in the Los An- 
geles, San Jose and Ventura areas. Dark brown to black, two to ten 
feet, rich in organic niatter, generally well drained. Stony phase 
contains gravel, slate fragments and granitic pebbles. SUBSOIL: 
same but heavier and more compact; gravelly soil. OCCURS: Gently 
sloping plain, in irregular-shaped bodies; level, on slightly depressed 
parts of valleys. ORIGIN: From slate and argillaceous sandstone and 
closely allied rocks; a mixture of the lighter soils derived from moun- 
tain waste, with the heavier alhivial and lacustrine deposits of the 
valley. CROPS: Lima beans, alfalfa, fruit, barley, corn, truck, grapes, 
strawberries, raspberries, onions, tomatoes, walnuts, lemons. Alkali 
present in appreciable quantities in low and poorly drained areas. 
PLACENTIA CLAY LOAM. Mapped as Placentia loam in the San 
Bernardino area. Reddish brown, micaceous, six feet deep, consider- 
able fine sand, poorly drained. OCCURS: Level, smooth. ORIGIN: 
Washings from the Placentia sandy loam. CROPS: Alfalfa. Some 
alkali due to seepage. 

SACRAMENTO CLAY LOAM. Mapped in the Stockton area. Dark 
to black, high per cent of organic matter, two to thirty feet deep, 
drainage poor. SUBSOIL: Light yellow, fine silty loam, fine sandy 
loam. OCCLTRS: Level, slightly inclined, grades into peats, adobes 
and loams. ORIGIN: River silts mixed with alluvial organic matter 
of the tidal fresh water marshes. CROPS: Alfalfa, redtop, rye grass, 
timothy, wheat, barley, oats, beans, vegetables, grains; peaches, apri- 
cots, pears and cherries where well drained. Generally free from 

SAN JOAQUIN CLAY LOAM. Mapped in the Madera area. Red 
to red brown; two to four feet. SUBSOIL: Red hardpan. OCCURS: 
In small local areas, hogwallows. ORIGIN: Colluvial and alluvial. 
CROP: Grain. 

SIERRA CLAY LOAM. Mapped in the Sacramento area. Light 
to deep red; three feet deep, drainage good. SUBSOIL: Bedrock. 
OCCURS: Prevailing type of the upper foothill region in the Sacra- 
mento area; outcropping ledges. ORIGIN: Weathering in place of 
underlying amphibolite diabase and limestone. CROPS: Grains, hay, 



120 Soils of Califobnia 

grapes; deciduous fruits; olives. NATIVE VEGETATION: Oak, gray 
leaf and yellow pine, shrubs. 

STOCKTON CLAY LOAM. Mapped in the xModesto-Turlock area. 
Yellow, 18 to 24 inches deep. SUBSOIL: Yellow adobe, silly fine 
sandy loam, hardpan. OCCURS: Smooth, flat, gently sloping flood 
plains. ORIGIN: Deposited by local streams. CROPS: Grain farm- 
ing, alfalfa, grapes, adapted to peaches, prunes, figs, berries and gar- 
den truck. Free from alkali. 

TASSAJERO CLAY LOAM. Mapped in the Livermore area. Dark 
brown, three feet. SUBSOIL: Same, lighter colored. OCCURS on 
valley floor, well drained. ORIGIN: Colluvial and alluvial. CROPS: 
Hay, grain, peaches, prunes, apricots. 

VINA CLAY LOAM. Mapped in the Red Bluflf area. Brown; pud- 
dles but is friable with tillage; two to six feet. SUBSOIL: Clay loam 
or loam, or volcanic conglomerate. OCCURS in broad tracts, below 
terraces, level, marked by abandoned water channels, overflowed, 
drainage sluggish. ORIGIN: Alluvial. VEGETATION: Valley oaks, 
wild oats. CROP: Grain, adapted to stone fruits. 
WILLOWS CLAY LOAM. Mapped in the Colusa and Woodland 
areas. Chocolate brown, yellow, three to six feet deep; drainage 
poor. SUBSOIL: Reddish brown, heavy, compact clay loam. OC- 
CURS: Occupies nearly flat depressions and low ridges of the valley 
plain. ORIGIN: Wash from slopes; deposits from small foothill 
streams. CROPS: Dry farming, pasture, alfalfa, grapes. When well 
drained is well adapted to alfalfa, sugar beets, wine, table and raism 
grapes, and general farm crops. Generally free from alkali. NATIVE 
VEGETATION: Willows. 

YOLO CLAY LOAM. Mapped in the Woodland area. Light to 
chocolate brown; three feet deep, well drained. SUBSOIL: Heavy 
clay loam. OCCURS: Flat to undulating along the side slopes of 
stream courses. ORIGIN: Alluvial. CROPS: Barley, wheat, hay, 
alfalfa, beets, garden truck, wine and raisin grapes. 

GRAVELLY CLAY LOAM 
PLEASANTON GRAVELLY CLAY LOAM. Mapped in the Liver- 
more area. Dark brown, 15 to 30 inches. SUBSOIL: Yellowish red 
to brown. OCCURS on rough ridges and in deep ravines. ORIGIN: 
Residual. CROPS^ Grazing. PHYSICAL ANALYSIS: Fine gravel, 
6.6; coarse and, 10.7; medium sand, 6.9; line sand, 14.4; very fine sand, 
9.4; silt, 26.1; clay, 25.6. 

SILTY CLAY LOAMS 

Fine Coarse Medium Fine Very fine 

gravel sand sand sand sand Silt Clay 

Elder 0.1 0.2 0.4 5.9 17.1 56.6 19.5 

Gridley 0.0 0.3 0.3 2.6 7.7 64.1 24.9 

Maywood 0.4 1.0 1.4 6.8 8.5 58.5 22.9 

Sacramento 0.0 0.2 0.3 6.4 14.5 61.5 17.3 

Santa Rita 0.5 1.4 1.4 4.0 5.7 60.3 26.4 

Willows 0.0 0.2 0.1 0.9 10.1 60.9 27.0 

Highest 0.5 1.4 1.4 6.8 17.1 64.1 27.0 

Lowest 0.0 0.2 0.1 0.9 5.7 56.6 17.3 

Average 0.1 0.5 0.6 4.4 10.6 60.3 23.0 



SiLTY Clay 121 

Soils that contain over 50 per cent of silt and clay are called silty 
clay loam, if they contain 20 to 30 per cent clay and over 50 per cent 
silt. They contain more of the fine sands than the silty clays and are 
therefore more friable, and not so liable to check and bake, and are 
easily tilled. They are compact and somewhat sticky and heavy when 
wet, and check some when dry; yet they rarely puddle and are friable 
under cultivation. 

ELDER SILTY CLAY LOAM. Mapped in the Red Blufif area. 
Gray, rich in organic matter, 24 to 30 inches. SUBSOIL: Heavy loam. 
OCCURS along creek bottoms. ORIGIN: Alluvial. CROPS: Grain, 
alfalfa. 

GRIDLEY SILTY CLAY LOAM. Mapped in the Marysville area. 
Dark reddish brown, without drainage. SUBSOIL: Black, heavy, clay 
loam, calcareous hardpan. OCCURS in irregular areas, lower than 
surrounding soils. ORIGIN: Alluvial. CROPS: Grain, pasture; 
adapted to alfalfa, grapes, etc., when drained. 

MAYWOOD SILTY CLAY LOAM. Mapped in the Red Bluff area. 
Smooth te.xture, very compact, cracks on drying, si.x feet. SUBSOIL: 
Same, lighter texture. OCCURS on plains, poorly drained. ORIGIN: 
Reworked alluvial. CROPS: Peaches, figs, pears, alfalfa. 
SACRAMENTO SILTY CLAY LOAM. Mapped in the Colusa, Red 
Blufif and Woodland areas. Dark gray to dark brown, micaceous, well 
drained, six feet. SUBSOIL: Same to clayish. OCCURS in narrow 
areas, level flood plains, lower draws, lower hill slopes, marked by 
sloughs. ORIGIN: Alluvial. CROPS: Sugar beets, prunes, citrus, 
sorghum, alfalfa, hops, fruit, truck. One of the most productive soils 
of the Colusa area. 

SANTA RITA SILTY CLAY LOAM. Mapped in the Livermore 
area. Dark gray, two to three feet. SUBSOIL: Same, of lighter color 
and texture. OCCURS on low flat land, marked by abandoned drain- 
age channels. ORIGIN: Originally swampy, but now naturally 
drained. CROPS: Grain, hay, alfalfa, truck. 

WILLOWS SILTY CLAY LOAM. Mapped in the Colusa area. 
Ashen gray, three to six feet. SUBSOIL: Brown, yellowish red, or 
reddish brown clay loam. OCCURS in irregular bodies, on the lower 
portions of the nearly level plains. ORIGIN: Alluvial. CROPS: 
Grazing, dry farming; when drained, adapted to alfalfa, sugar beets. 
Alkali in minor spots. 

LOAM ADOBES 

Fine Coarse Medium Pine Very fine 

gravel sand sand sand sand Silt Clay 

Placentia 0.7 1.9 2.3 14.0 26.8 30.5 21.5 

Sierra 6.0 13.4 7.0 15.1 10.2 25.4 21.1 

Stockton 0.5 3.0 3.2 15.2 21.6 30.8 25.9 

Average 2.4 6.1 4.1 14.7 19.5 28.9 22.8 

The loam adobes contain less silt than the clay or sandy adobes, 
and a higher percent of the coarser sands. They possess a better bal- 
anced quantity of the various sands than any of the other adobes. 
While they are sticky and plastic they respond readily to draining 



122 Soils of Califoenia 

and high cultivation and become favorite soils for grapes, and locally 
for walnuts, citrus, olives, grapes and general fruits. 
PLACENTIA LOAM ADOBE. Mapped as Fullerton sandy^ abode 
in the Los Angeles and Santa Ana areas. Locally called "Foothill 
soil" at Santa Ana. Brown to dark brown, three feet deep. SUB- 
SOIL: A lighter phase of the soil, yellowish gray indurated sand, 
sandy loam, sand, gravel, shaly sandstone. OCCURS: Rolling hills, 
sloping plains, foothills. CROPS: Walnuts, beans, grains, wheat, 
barley, citrus at Whittier, olives at Mirada, a great grain soil in south- 
ern California. Generally free from alkali. 

SIERRA LOAM ADOBE. Mapped as Sierra loam in the Sacramento 
area. Dark red, six inches to six feet deep. SUBSOIL: Residual red 
adobe. OCCURS on gently rolling slopes to steep rugged hill, rock 
outcrops, boulders. CROPS: Hay, grain, grapes and fruit. 
STOCKTON LOAM ADOBE. Mapped in the Stockton area. Black, 
thirty inches. SUBSOIL: Yellow, silty, clay loam. OCCURS: Level, 
low positions. ORIGIN: Lacustrine, modified by stream sediments. 
CROPS: Hay, grain, alfalfa, forage, grazing. Locally alkaline in 
spots. 

STONY LOAMS 
Fine Coarse Medium Fine Very fine 
gravel sand sand sand sand Silt Clay 

Sierra 5.3 9.3 4.9 14.5 10.8 32.3 22.4 

Tuscan 4.0 6.0 4.9 11.8 20.0 30.1 23.1 

Average 4.6 7.6 4.9 13.1 15.4 31.2 22.7 

SIERRA STONY LOAM. Mapped in the Sacramento area. Brown 
to black, six to thirty inches. SUBSOIL: Volcanic gravels, muds and 
breccia. OCCURS in irregular-shaped bodies, on summits of flat- 
topped volcanic ridges and knobs, surface strewn with boulders. 
ORIGIN: Residual, the decomposition of andesitic boulders and the 
volcanic muds and breccias. VEGETATION: Gray leaf pine, shrubs. 
CROPS: Grazing. 

TUSCAN STONY LOAM. Mapped in the Red Bluff area. Gray, 
very variable in texture, porous, leachy, 18 to 72 inches. SUBSOIL: 
Cemented volcanic material. OCCURS on level to rolling barren 
plains. ORIGIN: Residual from volcanic flows. CROPS: Sheep 
range. 

STONY CLAY LOAM 

VALLECITOS STONY CLAY LOAM. Mapped in the Livermore 
area. Red brown, 10 to 24 inches. SUBSOIL: Brown clay loam. 
OCCURS on hills and steep slopes with rock outcrops. ORIGIN: 
Residual from metamorphic rocks. VEGETATION: Field oak, live 
oak, buckeye, shrubs. CROPS: Grazing. PHYSICAL ANALYSIS: 
Fine gravel, 1.6; coarse sand, 5.6; medium sand, 4.5; fine sand, 8.5; 
very fine sand, 17.6; silt, 39.4; clay, 22.5. 

CLAY LOAM ADOBES 
Fine Coarse Medium Fine Very fine 
gravel sand sand sand sand Silt Clay 

Alamo 1.3 8.1 4.5 9.6 14.2 41.9 20.2 

Danville 0.0 0.6 1.3 6.7 27.6 36.9 27.2 

Dublin 0.0 0.4 1.4 16.0 24.9 27.3 30.1 



Sixty Clay 123 

Fine Coarse Medium Fine Very fine 

gravel sand sand sand sand Silt Clay 

Oxnard 0.9 ,3.2 2.1 7.6 10.8 36.0 35.4 

Pajaro 0.0 0.5 0.2 4.6 12.6 55.5 27.0 

Placentia 2.8 3.1 7.1 24.5 31.1 19.6 8.8 

Portersvllle 4.3 8.4 4.1 7.8 6.8 32.3 36.1 

San Joaquin 1.4 3.1 1.3 4.9 9.5 44.8 35.1 

Sites 0.0 3.6 5.0 16.3 12.5 36.8 25.7 

Sutter 1.0 5.1 4.3 14.2 8.0 41.7 25.8 

Stockton 0.6 1.9 3.0 8.3 14.5 42.6 27.9 

Watsonville 0.2 0.8 0.9 12.3 16.9 46.6 22.1 

Lowest 0.0 0.4 0.2 4.6 6.8 19.6 8.8 

Highest 4.3 8.4 5.0 16.0 31.1 55.5 36.1 

Average 1.0 3.2 2.8 9.4 13.2 38.5 21.8 

The clay loam abodes are similar to the loam adobes except in the 
larger percent of clay and silt. This makes them heavy and dense, 
and causes them to absorb and hold large quantities of water. They 
are hard to plow when dry and break up into clods. They are fairly 
easy to cultivate if well drained and not too wet. When too wet they 
become waxy and sticky and puddle, and bake and crack on drying. 
They are rich in plant food and have a higher agricultural value than 
the other adobes. These soils were formerly given up wholly to grain, 
hay, and grazing, but their value is now appreciated and drainage and 
proper handling is adding every year to their reputation for special 
crops. 

ALAMO CLAY LOAM ADOBE. Mapped in the Marysville area. 
Dark reddish brown to red, 12 to 30 inches deep. SUBSOIL: Dense 
hardpan. OCCURS in low positions, level, hog wallows, poorly 
drained. ORIGIN: Alluvial wash. CROPS: Pasture, sown to hay, 
adapted to Tokay grapes, etc. 

DANVILLE CLAY LOAM ADOBE. Mapped in the Livermore 
area. Brown to black, carries some shale and angular rock fragments, 
24 to 36 inches. SUBSOIL: Clay loam. OCCURS on valley floor. 
ORIGIN: Colluvial and alluvial. CROPS: Dry farmed to grain, 
deciduous fruits do well under irrigation. 

DUBLIN CLAY LOAM ADOBE. Mapped in the Livermore area. 
Brown to black, carries shale fragments, 18 to 48 inches. SUBSOIL: 
Yellow clay loam. OCCURS on valley bottom and sides. ORIGIN: 
Colluvial and alluvial. CROPS: Dry farmed to hay and grain. 
OXNARD CLAY LOAM ADOBE. Mapped as San Joaquin black 
adobe in the Los Angeles, Lower Salinas Valley, San Bernardino, San 
Gabriel, Santa Ana and Ventura areas. Black to dark brown, three 
to six feet, usually well drained. SUBSOIL: Shale, shaly sand- 
stone, sandy loam, sand, gravel. OCCURS along river beds, capping 
shaly hills, on level valley floors, low rolling hills, slough and lake 
bottoms. ORIGIN: Weathering of argillaceous sandstones and shale 
in place, or the washings from them. CROPS: Grain, alfalfa, corn, 
barley. Generally free from alkali. 

PAJARO CLAY LOAM ADOBE. Mapped in the Pajaro area. 
Black, high percent of lime and humus, poorly drained, apt to be 
water-logged, naturally very fertile, three feet deep. SUBSOIL: Com- 
pact clay loam, or siity clay loam. OCCURS on low elevations along 
rivers. ORIGIN: Composed of weathered shale, the finer or clay 



124 Soils of California 

particles of which were deposited in quiet waters. CROPS: Apples, 
alfalfa, strawberries, loganberries, raspberries, blackberries, sugar 
beets, beans, onions, barley. 

PLACENTIA CLAY LOAM ADOBE. Mapped as Sierra adobe in 
the Fresno area. Reddish. SUBSOIL: Same. OCCURS: Foothills, 
steep land. ORIGIN: Normal product of the weathering of the gran- 
itic rocks of the foothills. CROPS: Dry farming. 
PORTERSVILLE CLAY LOAM ADOBE. Mapped in the Porters- 
ville area. Dark brown, two to six feet deep, carries subangular frag- 
ments. SUBSOIL: Reddish brown to almost white, marly. OCCURS: 
Locally called "Dry bog adobe," found on the outer slopes of the foot- 
hills of the Coast Range, quite steep. ORIGIN: Residual, from 
weathering and decomposition of the underlying granitic rocks, which 
are associated with magnesite and lime. CROPS: Formerly to grain, 
especially adapted to oranges and lemons. Free from alkali. 
SAN JOAQUIN CLAY LOAM ADOBE. Mapped as San Joaquin 
red adobe in the Sacramento area. Red, two to three feet. SUB- 
SOIL: Red sandy hardpan. OCCURS: Lower slopes of the valley 
plains, smooth. ORIGIN: Alluvial. CROPS: Grain and hay. 
SITES CLAY LOAM ADOBE. Mapped in the Colusa and Wood- 
land areas. Reddish to gray browns, six feet deep, gravelly. SUB- 
SOIL: Silt, red clay, clay loam adobe, red clay hardpan, gravelly loam, 
cemented gravel. OCCURS on lower undulating foothills of the 
Coast Range. ORIGIN: Weathering from sandstone, shale and con- 
glomerate. CROPS: Dry farmed, grazing, grain. 

SUTTER CLAY LOAM ADOBE. Mapped in the Marysville area. 
Chocolate brown, two to three inches. SUBSOIL: Same, lighter 
brown. OCCURS in irregular-shaped small bodies in the smaller val- 
leys. ORIGIN: Wash from the volcanic rocks of the Marysville 
Buttes, and from adjacent soils. CROPS: Grain cut for hay. 
STOCKTON CLAY LOAM ADOBE. Mapped in the Stockton area. 
Mapped as San Joaquin black adobe in the San Jose, Hanford and 
Fresno areas. Locally called "Dry bog soil." Black, three to six feet 
deep, poorly drained. SUBSOIL: Yellow, heavy silty or silty clay 
hardpan. OCCURS on low level flat plains, lower levels or depres- 
sions of valley floor. ORIGIN: Old lacustrine or swamp deposits 
modified. CROPS: Alfalfa, wheat, rye, barley, forage grass, veget- 
ables, flower seeds, strawberries, raspberries, sugar beets, apples, 
I)ears orunes at San Jose and Santa Clara. Generally free from alkali. 
WATSONVILLE CLAY LOAM ADOBE. Mapped in the Pajaro 
area. Black to dark brown, 20 to 30 inches deep. SUBSOIL: Yellow, 
gritty clay loam. OCCURS: Lowest hills and their slopes adjacent 
to the river. ORIGIN: Residual from decomposing shales. CROPS: 
Grains, pears, eucalyptus. 



CHAPTER XVII 



SILT LOAMS. LOAMS. 



Fine Coarse Medium Fine Very fine 

gravel sand sand sand sand Silt Clay 

Feather 0.0 0.2 0.2 0.7 4.2 81.1 13.4 

Gila 0.5 0.3 0.3 2.7 10.3 54.8 31.3 

Hanford 0.2 0.8 0.7 5.5 13.3 58.0 19.5 

Marysville 0.0 0.8 0.5 5.2 13.7 57.1 22.6 

Maywood 1.6 2.2 1.9 9.5 11.3 57.3 15.9 

Oxnard 0.0 0.5 0.7 8.1 10.5 55.9 19.9 

Pajaro 0.0 0.1 0.1 10.6 22.2 53.3 12.7 

Sacramento 0.0 0.6 1.0 8.8 9.6 64.1 16.0 

Sites 0.5 3.1 3.2 6.0 8.6 60.5 18.1 

Stockton 1.0 6.6 6.0 16.7 15.3 53.5 18.8 

Yolo 0.0 0.1 0.1 1.2 5.0 69.1 24.4 

Highest 1.6 6.6 6.0 16.7 22.2 81.1 24.4 

Lowest 0.0 0.1 0.1 0.7 4.2 53.3 12.7 

Average 0.3 1.4 1.3 6.8 11.2 60.4 19.3 

When soils contain over 50 per cent of silt and clay they are 
called silt loams, if they contain less than 20 per cent clay or over SO 
per cent silt. They are finer than the fine sandy loams, and the par- 
ticles are very uniform in size. They are fine, close, and dense in tex- 
ture, retentive of moisture; very sticky and liable to puddle if plowed 
when wet, but loose and friable when dry. If plowed when too dry, 
they form large hard clods. Under cultivation they break into a fine 
friable loam. They are generally rich in organic matter. 
ELDER SILT LOAM. Mapped in the Red Bluflf area. Gray, smooth, 
friable, six feet. SUBSOIL: Coarse alluvium. OCCURS as broad 
alluvial bottoms, well drained. ORIGIN: Alluvial. CROPS: Dry 
farmed to grains, adapted to prunes, peaches, wheat, barley, alfalfa, 
sugar beets, melons, truck. 

FEATHER SILT LOAM. Mapped in the Marysville area. Light to 
dark brown, shale particles, six feet. SUBSOIL: Similar but heavier. 
OCCURS in river bottoms. ORIGIN: Alluvial deposited by creeks, 
subject to annual overflow. Locally called "Black Land." CROPS: 
Alfalfa, corn, sorghum; adapted to truck crops and small fruits. 
GILA SILT LOAM. Mapped as Imperial silt loam in the Yuma- 
California area. Mapped as Santiago silt loam, Yuma area. Gray to 
brown, poorly drained, 12 to 30 inches. SUBSOIL: Sand, loam, clays. 
OCCURS on lands overflowed by annual river floods, in low places, 
comparatively level, in long strips. ORIGIN: Sediments deposited 
after the river floods have been robbed of their fine sand. CROPS: 
Kaffir, Egyptian and Indian corn, Milo maize, millet, sorghum, garden 
vegetables, melons, pumpkins. Often free from alkali. 
HANFORD SILT LOAM. Mapped in the Modesto-Turlock area. 
Mapped as Santiago silt loam in the Los Angeles, Lower Salinas Val- 
ley areas. Mapped as Sacramento silt loam in the Sacramento area, 



126 Soils of California 

and mapped as Fresno fine sandy loam in the San Jose area. Brown 
to black, yellowish to gray, micaceous, very sticky, two to six feet, wet 
and poorly drained in places; light colored are friable and the dark 
colored are heavy. SUBSOIL: Sand, silt, brown or dark clay loam, 
lighter sediments. OCCURS in long narrow strips in irregular-shaped 
bodies, on flat plains, river terraces, in slight depressions, level, locally 
subject to overflow. ORIGIN: Alluvial, deposited along stream flood 
plains and in depression by slack silt-laden waters. CROPS: Alfalfa, 
strawberries, raspberries, beans, potatoes, sugar beets, hops, asparagus. 
Generally small amounts of alkali near the surface, heavy locally. 

MARYSVILLE SILT LOAM. Mapped in the Marysville area. 
Light brown, poorly drained, overflowed, 18 inches to 4 feet. SUB- 
SOIL: Reddish brown sticky silty clay loam, gray hardpan. OCCURS 
at junction of streams subject to floods. ORIGIN: Alluvial. CROPS: 
Where drainage is possible, alfalfa, grapes, stone fruits. 
MAYWOOD SILT LOAM. Mapped in the Red BlufJ area. Yellow- 
ish gray, smooth texture, compact, sticky when wet, friable when 
properly handled, uniform, 30 to 36 inches. SUBSOIL: Silty chiy 
loam. OCCURS along minor streams. Drainage adequate. ORIGIN: 
Alluvial. VEGETATION: Oaks, willows. CROPS: Dry farming, 
orchards. 

OXNARD SILT LOAM. Mapped in the San Jose and Ventura areas. 
That mapped as Oxnard silt loam in the Bakersfield area has been 
reclassified as Hanford clay loam. Brownish, well drained; heavier 
phases resemble true adobe. OCCURS in bodies of irregular outline, 
between valley bottoms and base of mountains, slightly undulating, 
level, smooth plains. ORIGIN: Deposition of finer particles held in 
suspension by flood waters, disintegrated sandstone mixed with 
organic matter. CROPS: Very fertile — prunes, apricots, cherries, 
apples, small fruits, hay, lima beans, walnuts, citrus fruits. Some 
alkali where drainage is deficient. 

PAJARO SILT LOAM. Mapped in the Pajaro area. Brown, smooth, 
micaceous, three feet. SUBSOIL: Lighter in texture and color, 30 
feet. OCCURS parallel to the rivers, scalloped by river floods. 
ORIGIN: From weathered and transported shales. CROPS: Very 
fertile; apples, alfalfa, sugar beets, beans, potatoes, strawberries, 
loganberries, blackberries, raspberries. PHASE: Light silt loam, 
mapped in the Pajaro area, light brown, very micaceous, six feet, sim- 
ilar subsoil. OCCURS: Low lying, occasionally flooded. CROPS: 
Apples, berries, truck gardening. 

SACRAMENTO SILT LOAM. Mapped in the Colusa, Marysville, 
Modesto-Turlock, Woodland, Red Bluff and Redding areas. That 
mapped as Sacramento silt loam in the Sacramento area has been 
reclassified as Hanford silt loam. Light to yellowish brown, dark 
brown, drab, gray, micaceous, often gravelly, well drained, 18 inches 
to 20 feet. SUBSOIL: Same, deeper color, compact, sand, gravel. 
OCCURS: Stream bottoms, in narrow bodies, level. ORIGIN: Allu- 
vial deposited by stream floods. CROPS: Wheat, barley, grapes, 
alfalfa, hops, broom corn, sugar beets, truck, peaches, prunes, pears. 
Free from excess of alkali. 



Silt Loams Loams 



127 



SITES SILT LOAM. Mapped in the Woodland area. Yellow to red 
brown, smooth texture, some water-worn gravel, two feet. SUB- 
SOIL: Dark red loam, clay loam, sandy loam. OCCURS as broad 
slopes near base of hills. ORIGIN: Residual and colluvial. CROPS: 
Barley, wheat, with proper cultivation adapted to grapes, almonds, 
apricots. 

STOCKTON SILT LOAM. Mapped in the Stockton area. Light 
brown, well drained, six feet. SUBSOIL: Lighter colored, more com- 
pact, hardpan. OCCURS in large irregular-shaped level bodies. 
ORIGIN: From a large variety of rocks. CROPS: Vegetables, wheat, 
barley, oats, alfalfa, root crops, almonds, cherries, peaches, late grapes. 
Free from alkali. 

TEHAMA SILT LOAM. Mapped in the Red Bluflf area. Yellow 
brown to red yellow, puddles, 10 to 20 inches. SUBSOIL: Brown 
silty clay loam. OCCURS on intermediate plains of gentle slope, 
poorly drained. ORIGIN: Recent alluvial from Red Bluff formation. 
CROP: Dry farmed to grain; under irrigation adapted to berry, 
alfalfa, grapes, farm crops. 

VINA SILT LOAM. Mapped in the Red Bluff area. Brown, six 
feet. SUBSOIL: Volcanic gravel. OCCURS bordering stream chan- 
nels. ORIGIN: Alluvial. VEGETATION: Oak, cottonwood, wil- 
lows, sycamore, wild oats. CROPS: Alfalfa, grain, peaches, prunes, 
grapes, sugar beets, truck. 

YOLO SILT LOAM. Mapped in the Woodland area. Light to dark 
brown, heavy, three feet, good drainage. SUBSOIL: Brown silty 
clay, loose sandy loam. OCCURS in large irregular-shaped bodies, 
along sides of creeks, on slopes approaching the ridges along stream 
channels. CROPS: Dry farmed to grain, well adapted to a wide 
range of crops if irrigated; alfalfa, sugar beets, garden vegetables, etc. 









LOAMS 












Fine 


Coarse 


Medium 


Fine 


Very fine 








gravel 


sand 


sand 


sand 


sand 


Silt 


Clay 


Arbuckle . . . 


.. . 0.0 


0.7 


1.2 


6.2 


23.1 


45.6 


23.1 


Arnold 


... 2.9 


12.1 


6.7 


16.9 


7.3 


44.2 


10.4 


Bear 


... 0.2 


1.7 
3.0 


1.8 
5.4 


7.6 
22.1 


17.0 
5.4 


49.2 
45.2 


22.4 


Corralitos . . . 


... 0.1 


18.7 


Dublin 


.. . 0.6 


2.4 


3.9 


18.4 


31.7 


25.3 


17.5 


Esparto .... 


... 0.2 


1.5 


3.1 


18.9 


21.4 


32.6 


22.2 


Feather. . . . 


... 0.0 


0.9 


1.1 


11.2 


25.8 


45.2 


15.9 


Fresno 


... 0.4 


3.6 


3.0 


11.2 


18.8 


40.7 


22.1 


Gila 


... 0.0 


0.3 
4.4 
6.1 


1.5 
3.3 
6.7 


15.2 
13.6 
17.4 


29.4 

17.1 

9.6 


43.8 
40.6 
39.8 


9.5 


Gridley 


... 0.2 


20.7 


Hanford .... 


... 1.7 


18.8 


Honicut .... 


... 0.6 


3.9 


2.9 


13.4 


14.0 


46.8 


18.5 


Llvermore . . 


... 0.3 


1.2 


2.5 


15.7 


29.9 


32.1 


18.2 


Maywood . . . 


... 1.2 


2.4 


2.8 


13.1 


19.3 


47.2 


13.5 


Mocho 


... 2.6 


4.0 

8.8 


6.4 

6.5 


20.0 
18.4 


17.7 
9.9 


34.9 
37.9 


14.4 


Modesto .... 


... 1.9 


16.1 


Oxnard 


... 0.8 


3.4 


3.9 


23.0 


7.4 


42.3 


15.4 




... 0.0 


0.4 
4.0 


0.4 
4.8 


7.6 
19.6 


19.5 
10.9 


54.8 
39.6 


16.4 


Placentia . . . 


... 1.8 


16.8 


Pleasanton . 


... 2.9 


3.9 


3.7 


10.2 


19.2 


44.1 


15.8 


Portersville . . 


... 4.0 


11.2 


9.0 


23.9 


8.6 


22.5 


20.8 


Redding .... 


. . . "4.4 


11.4 


5.5 


13.1 


14.4 


34.8 


16.6 


Sacramento . 


... 0.9 


2.7 


3.0 


14.9 


18.0 


45.3 


14.4 



128 



Soils of California 



Fine Coarse Medium Fine Very fine 

gravel sand sand sand sand Silt Clay 

Salsipuedes 1.7 6.4 4.9 19.4 10.8 41.0 16.1 

San Joaquin .... 1.8 8.2 5.6 13.5 13.3 40.7 16.5 

Santiago 0.0 2.5 1.6 8.8 24.7 43.0 15.9 

Santa Cruz 1.1 8.6 8.6 30.1 5.2 23.9 22.0 

Santa Rita 0.1 0.6 1.3 6.4 32.2 41.3 17.9 

Sierra 3.3 10.6 5.9 11.9 8.9 45.1 14.3 

Sites 1.6 3.4 3.1 17 6 20.1 39.1 14.8 

Stockton 0.3 6.8 6.0 25.3 15.6 26.5 18.9 

Sunol 0.2 0.9 1.7 10.9 15.4 48.3 22.4 

Sutter 1.5 5.2 5.4 13.5 11.8 37.9 24.8 

Ulmar 0.8 3.0 4.4 13.2 20.8 37.1 20.3 

Vallecitos 0.2 2.3 5.9 20.8 28.7 22.7 19.2 

Vina 1.4 2.8 3.6 12.5 19.1 45.8 14.8 

Watsonville 1.3 6.5 9.3 22.3 11.7 26.9 22.0 

Willows 0.9 2.6 2.6 10.6 12.1 44.8 25.9 

Yolo 0.1 0.4 0.9 9.5 27.3 43.5 18.2 

Highest 4.4 12.1 9.3 30.1 32.2 54.8 25.9 

Lowest 0.0 0.3 0.4 6.2 5.2 22.5 9.5 

Average 0.2 3.9 4.4 17.3 16.7 39.7 17.9 

If soils contain over 50 per cent of silt and clay they are called 
loam, if they contain less than 20 per cent of clay and less than 50 
per cent of silt. They are the most useful all-around soils, combining 
the lightness and earliness of the sands, with the strength and reten- 
tiveness of the clays. They are smooth, uniform, open, porous, and 
have high capillary power. While naturally compact and liable to be 
sticky or even puddle when wet, they are loose and powdery when dry 
and easily cultivated where well drained, and maintain an excellent 
tilth. They work easily and do not crack or crust. Water moves 
easily in them and to long distances. 

ARBUCKLE LOAM, Mapped in the Woodland area. Light to gray 
brown. SUBSOII^: Variable in texture, brown sandy loam. loam. 
OCCURS near present or former streams, sloping, slightly uneven, 
well drained. ORIGIN: Lacustrine, alluvial. CROPS: Wheat, al- 
monds, raisins, fine grape soil, adapted to alfalfa, fruit, Kaffir and 
Egyptian corn, sorghum, beets and general farm crops. 
ARNOLD LOAM. Mapped in the Modesto-Turlock area. Grayish 
brown, red, black, mottled, light, sandy, ten to fifteen inches. SUB- 
SOIL: Heavy loam. OCCURS: Covering undulating hills. ORIGIN: 
Lacustrine, alluvial. CROPS: Dry farming to grain. 
BEAR LOAM. Mapped in the Marvsville area. Reddish brown, well 
drained, four to six feet deep. OCCURS: Bottom lands. ORIGIN: 
Material washed from adjaceint plains soils. CROPS: Grain, hay. 
alfalfa, stone fruits, grapes, hops. 

CORNING LOAM. Mapped in the Red Bluff area. Reddish, slightly 
sticky, with tendency to clog and puddle, sixteen to thirty inches. 
SUBSOIL: Clay or clav loam. OCCURS on upland plains, level to 
gentlv rolling. ORIGIN: Alluvium from Red Bluff formation. 
CROPS: Dry farmed to grain. When irrigated it is adapted to 
peaches, almonds, iigs, berries, grapes, etc. 

CORRALITOS LOAM. Mapped in the Pajaro area. Chocolate 
brown, micaceous, three feet deep. SUBSOIL: Brown to yellowish 
brown micaceous loam, thirty feet deep. OCCURS: Oval-shaped body 
on higher plain. ORIGIN: Washings from rotten shales from adja- 



Silt Loams Loams 129 

cent hills, mixed with creek alluvium. CROPS: Generally devoted to 
grazing, dry farming to grain, apples, apricots, prunes, English wal- 
nuts, vegetables, berries, etc. 

DUBLIN LOAM. Mapped in the Livermore area. Dark brown to 
black, two to three feet. SUBSOIL: Gray brown silt loam. OCCURS 
along creek bottoms. ORIGIN: Colluvial. VEGETATION: Oak, 
willow, sycamore. CROPS: Dry farmed to hay and grain, adapted 
under irrigation to fruit, truck, alfalfa. 

ESPARTO LOAM. Mapped in the Woodland area. Brown to yel- 
lowish brown, well drained, 24 inches. SUBSOIL: Brown clay loam. 
OCCURS: Moderate elevations near sloughs. ORIGIN: Recent allu- 
vial. CROPS: Excellent grape soil, apricots, almonds, plums, olives, 
figs, alfalfa. Free from alkali. 

FEATHER LOAM. Mapped in the Marysville area. Reddish brown, 
poorly drained, named for the Feather River; six feet. SUBSOIL: 
Heavier. OCCURS along river bottoms, flooded. ORIGIN: Alluvial 
and sedimentary, and subject to alterations by floods. CROPS: Where 
reclaimed, excellent for alfalfa, peaches, pears. 

FRESNO LOAM, Mapped in the Modesto-Turlock and Porters- 
ville areas. Mapped as Maricopa loam in the Fresno area. Chocolate 
to gray brown, red, micaceous, one to six feet. SUBSOIL: Mica- 
ceous fine sand, fine sandy loam. OCCURS in low flat tracts, uneven 
surface, offer hummocky. ORIGIN: from very fine sediments laid 
down at former periods by slack water from old river channels, lacus- 
trine. CROPS: Often uncultivated owing to lack of water, dry 
farming to grain, grazing; adapted to alfalfa, corn, grain, etc., where 
irrigated. Impregnated in places with soluble alkali salts and common 
salt. 

GILA LOAM. Mapped as Imperial fine sandy loam in the Yuma- 
California area. Three to twenty feet deep. SUBSOIL: Coarser sand, 
fine sandy loam. OCCURS in long narrow strips along the Colorado 
River, smooth, often covered with cottonwood, willow or arrow-weed. 
ORIGIN: Sediments deposited by river in the annual floods. CROPS: 
All shallow rooted vines, fruits, vegetables. Sometimes heavy in 
alkali, but can generally be reclaimed by one year's heavy flooding. 
GRIDLEY LOAM. Mapped in the Marysville area. A reddish 
brown, light, little natural surface drainage, two to six feet. SUB- 
SOIL: Black, clay loam, adobe-like, gray calcareous hardpan. 
OCCURS: Extensive level plain, surface slightly uneven, contains 
depressions with no outlet. ORIGIN: Sedimentary altered by river 
floods. CROPS: Requires drainage ditches; alfalfa, fruits, peaches, 
pears, apricots, apples, grapes, almonds, figs. 

HANFORD LOAM. Mapped in the Portersville area. Dark gray, 
28 to 60 inches. SUBSOIL: heavy yellowish or reddish brown loam, 
light clay loam. OCCURS: Level, no local drainage. ORIGIN: 
Alluvial material deposited in quiet water. CROPS: Grazing, alfalfa. 
HONICUT LOAM. Mapped in the Marysville area. Reddish brown, 
two feet. SUBSOIL: Dark red loam. OCCURS: Level, well drained. 
ORIGIN: Alluvial washed from higher soils. CROPS: Truck, alfalfa, 
berries, figs, stone fruits. 



130 Soils of California 

LIVERMORE LOAM, Mapped in the Livermore area. Dark brown, 
thirty to thirty-six inches. SUBSOIL: Light brown silty loam. 
OCCURS as strips and irregular bodies on valley floor, level, marked 
by abandoned stream channels, well drained. ORIGIN: Colluvial 
and alluvial. CROP: Hay, barley, wheat, grapes, almonds. 
MAYWOOD LOAM. Mapped in the Red Bluflf area. Grayish or 
yellowish gray, two to six feet. SUBSOIL: Yellow clay loam. OC- 
CURS on gently rolling valley plains. ORIGIN: Reworked alluvial 
material. CROP: Dry farmed to grain, adapted to almonds, 
olives, etc. 

MOCHO LOAM. Mapped in the Livermore area. Dark brown to 
drab, eighteen to twenty-four inches. SUBSOIL: Gray brown sands. 
OCCURS on level land along creeks. ORIGIN: Alluvial wash from 
adjacent soils. CROPS: Hay, grain, truck, fruit. 
MODESTO LOAM. Mapped in the Modesto-Turlock area. Choco- 
alte brown, gray, coarse granite sand, twelve inches. SUBSOIL: 
Clay loam, sandy loam. OCCURS: Uneven, level stretches with hog- 
wallow depressions, hummocks. ORIGIN: From old overflowed chan- 
nel deposits. CROPS: Alfalfa, grapes, peaches where drained. Ele- 
vated portions free from alkali. 

OXNARD LOAM. Mapped in the San Bernardino area. Mapped as 
Fresno line sandy loam in the Ventura area. That mapped as Oxnard 
loam in the San Jose and Ventura areas has been reclassified as Ox- 
nard clay loam. Gray, sticky, micaceous, drainage good, three to six 
feet deep. SUBSOIL: Dark adobe. OCCURS: Level, smooth, gently 
sloping plains, hillsides, skirting gullies. ORIGIN: Derived from 
shale and shaly sandstone, unconsolidated sandstones. CROPS: Pas- 
ture, wheat, alfalfa, lima beans, English walnuts, citrus fruits. Free 
from alkali, where well drained. 

PAJARO LOAM. Mapped in the Pajaro area. Dark brown or black, 
heavy, micaceous, high percent of humus, generous lime content, 
twelve to eighteen inches. SUBSOIL: Light yellow silt loam, thirty 
feet deep. OCCURS: Along the lower lands of the rivers and creeks. 
ORIGIN: Alluvial and sedimentary. CROPS: Apples, alfalfa, sugar 
beets, beans, potatoes, onions, strawberries, blackberries, loganberries. 
PLACENTIA LOAM. Mapped as Placentia sandy loam in the Ven- 
tura area. Mapped as Los Angeles sandy loam in the Los Angeles 
area. That mapped as Placentia loam in the San Bernardino area has 
been reclassified as Placentia clay loam. Reddish brown to light 
brown, two to six feet deep. SUBSOIL: Hardpan, decayed rock, yel- 
lowish to gray. OCCURS on low rolling hills, steep grades, rough 
hills. ORIGIN: Disintegration of sandstones and shale in place, 
wash from sandstone. CROPS: Barley, corn, blackeyed beans, apri- 
cots, oranges. Generally free from alkali. 

PLEASANTON LOAM. Mapped in the Pleasanton area. Brown, 
high percent of gravel, sticky, forms surface crust on drying that yields 
readily to tillage, twelve to thirty inches. SUBSOIL: Reddish clay 
loam. OCCURS on the lower slopes of the hills. ORIGIN: Sedi- 
mentary. VEGETATION: Oaks. CROPS: Wine grapes, adapted to 
fruit, alfalfa, truck. 



Silt Loams Loams 131 

PORTERSVILLE LOAM. Mapped in the Portersville area. Gray- 
ish red, micaceous, eighteen inches to six feet deep. SUBSOIL: 
Granitic rock. OCCURS: Granitic foothills and mesas. ORIGIN: 
Residual, from the underlying granitic rocks, more or less modified 
by rain wash and alluvial action. CROPS: Dry farming to grain, 
pasture, citrus fruits. Free from alkali. 

REDDING LOAM. Mapped in the Redding area. Light red to red- 
dish gray, eight to twelve inches. SUBSOIL: Dark red, heavy, clay 
loam, sandy clay hardpan. OCCURS: Upland plains. CROPS: Graz- 
ing, wheat, small fruits, table and wine grapes where locally deep. 
SACRAMENTO LOAM. Mapped in the Colusa and Redding areas. 
Light to dark brown, dark gray, drab, three to six feet. SUBSOIL: 
Sands, gravel. OCCURS in irregular bodies, long narrow areas, level 
and gently sloping, valley plains, stream bottoms. ORIGIN: Recent, 
alluvial. CROPS: Alfalfa, beets, grazing, dry farming to grain. 

SALSIPUEDES LOAM. Mapped in the Pajaro area. Dark brown, 
gritty, three feet deep. SUBSOIL: Brown loam, sandy loam. OC- 
CURS: Slope of foothills, valley. ORIGIN: CoUuvial from shale, 
and wash from adjacent hills. CROPS: Apple, prune, apricot. 

SAN JOAQUIN LOAM. Mapped in the Colusa, Modesto-Turlock, 
Marysville, and Stockton areas. Reddish to yellowish gray, dark red, 
texture variable, often gravelly, ten inches to three feet. SUBSOIL: 
Brown to reddish brown, heavy clay loam, yellow to red hardpan. 
OCCURS on gentle slopes, valley plains, foothills, rolling uplands. 
ORIGIN: Modified early Pleistocene deposits. CROPS: Grain, with 
irrigation, alfalfa, fruit, Tokay grapes, general farm crops. 
SANTIAGO LOAM. Mapped in the Santa Ana area, three to six 
feet. SUBSOIL: Sand, gravel. OCCURS: Level to rough and 
broken. CROPS: Wheat, barley. 

SANTA CRUZ LOAM. Mapped in the Pajaro area. Brown, filled 
with lenticular shale fragments, gritty, thirty inches. SUBSOIL: Yel- 
low or drab silt loam. OCCURS: Higher ridges and slopes along 
creeks and ravines. ORIGIN: From weathering of shale in place. 
CROPS: Apples, apricots. 

SANTA RITA LOAM. Mapped in the Livermore area. Dark gray 
to black, three feet. SUBSOIL: Gray silt loam. OCCURS on level 
land. Drainage good. ORIGIN: Alluvial formed under swamp con- 
ditions. CROPS: Hops, sugar beets, alfalfa. 

SIERRA LOAM. Mapped in the Marysville area. That mapped as 
Sierra loam in the Sacramento area is Sierra loam adobe. Red, con- 
tains sharp angular rock fragments from the lone formation. SUB- 
SOIL: Light brown to gray loam. OCCURS: Slopes of the lower 
foothills of the Sierras. ORIGIN: Mainly residual, but along stream 
courses partially colluvial, from the weathering of the underlying 
andesite, amphibolitic rocks, and diabase; and from the lone forma- 
tion. CROPS: Citrus fruits and olives where irrigated. 
SITES LOAM. Mapped in the Colusa and Woodland areas. Light 
gray, reddish brown, heavy, well drained, fourteen inches to four feet. 
SUBSOIL: Light colored argillaceous sandstones, mixed with some 



132 Soils of California 

shale, limestone, loams, etc. OCCURS in small irregular patches on 
summits and slopes of lower foothills. ORIGIN: Colluvial, residual 
from subsoil materials. CROPS: Grain and grazing, adapted to wide 
range of crops. 

STOCKTON LOAM. Mapped in the Stockton and Modesto-Turlock 
areas. Chocolate brown to black, micaceous, one to six feet. SUB- 
SOIL: Fine silty or sandy loam. OCCURS in irregular bodies, elong- 
ated bodies along streams, foot of terraces, generally level. ORIGIN: 
Alluvial, resulting from the deposition of heterogenous sediments in 
ancient lakes or bays and streams, modified by admixture of more 
recent sediments laid down by existing streams. CROPS: Alfalfa, 
onions, cabbage, grains, hay, peaches, prunes, walnuts, grapes, garden 
truck. Generally free from alkali. 

SUNOL LOAM. Mapped in the Livermore area. Brown, carries 
angular rock fragments, twenty-four to thirty-six inches. SUBSOIL: 
Clay loam. OCCURS as level floor of valley. ORIGIN: Colluvial. 
CROPS: Hay, grain, fruit and alfalfa under irrigation. 
SUTTER LOAM. Mapped in the Marysville area. Grayish, some 
tine gravel, eighteen inches to six feet. OCCURS: Irregular or sloping 
lands, below edge of Buttes, in small valleys, sometimes subject to 
overflow, sometimes a slight hog-wallow surface. ORIGIN: Largely 
colluvial washed from adjacent buttes and altered by alluvial deposits. 
CROPS: Pasturage, alfalfa, almonds. 

ULMAR LOAM. Mapped in the Livermore area. Brown, fifteen 
to twenty-four inches. SUBSOIL: Yellow or brown clay, and cal- 
careous hardpan. OCCURS: Level, marked by hog-wallows. ORIGIN: 
Colluvial and alluvial. CROPS: Hay, grain, grazing, under irrigation 
adapted to strawberries, alfalfa, truck. 

VALLECITOS LOAM. Mapped in the Livermore area. Reddish 
brown, fifteen to thirty inches. SUBSOIL: Yellow clay loam. 
OCCURS on rough hills and in deep ravines. ORIGIN: Residual 
from metamorphic rocks. VEGETATION: Live oak, field oak, buck- 
eye. CROPS: Hay, grain, grazing. 

VINA LOAM. Mapped in the Red Bluff area. Locally called "Park 
Soil." Red brown, two to six feet. SUBSOIL: Gravel. OCCURS 
on fan-shaped stream deltas, gently sloping, often abrupt terraces. 
ORIGIN: Part of a dissected plain. VEGETATION: Blue oak, cea- 
nothus, chaparral. CROPS: Grain, berries, melons, peaches. 

WATSONVILLE LOAM. Mapped in the Pajaro area. Dark brown 
to gray, high in humus, twenty inches to four feet. SUBSOIL: Red- 
dish yellow clay loam, hardpan, disintegrated shales. OCCURS: 
Lower portions of ridges and hills, low hills. ORIGIN: Residual 
from the underlying shales. CROPS: Grain, apples, raspberries, 
blackberries, strawberries, pears, grapes. 

WILLOWS LOAM. Mapped in the Colusa and Woodland areas. 
Reddish gray, light red, yellow brown, some sharp sand, generally 
well drained, ten to eighteen inches. SUBSOIL: Reddish brown clay 
loam, compact, adobe-like. OCCURS in irregular shaped bodies, 
sloping valley plains near foothills, uneven, hog-wallow mounds. 



Silt Loams Loams 133 

ORIGIN: Alluvial, weathering of the sandstones of the foothills. 
CROPS: Raisin, table, wine grapes, alfalfa, sugar beets, sorghum, 
Egyptian corn, tree fruits, small fruits. Free from alkali. 
YOLO LOAM. Mapped in the Woodland area. Dark brown, two 
to six feet. SUBSOIL: Silty, or sandy, loam. OCCURS: Plains ele- 
vated above surrounding areas, undulating ridges. ORIGIN: Depos- 
ited by creek waters. CROPS: Peaches, almonds, prunes, grapes. 
Rarely contains alkali. 



CHAPTER XVIII 
SANDY ADOBES 

GRAVELLY FINE SANDY LOAMS. STONY SANDY 

LOAMS. GRAVELLY SANDY LOAMS. 

GRAVELLY LOAMS. 

Fine Coarse Medium Fine Very fine 

gravel sand sand sand sand Silt Clay 

Placentia 2.0 4.1 .3.7 17.1 17.4 33.9 21.4 

San Joaquin .... 1.1 4.5 12.1 23.2 22.1 23.9 10.5 

Sierra 0.9 3.2 3.4 10.3 17.4 45.4 19.3 

Average 1.3 3.9 6.4 16.9 18.9 34.4 17.0 

As the name indicates, they contain the highest per cent of sand 
of all the adobes. They contain also the least clay, and some fine 
gravel and coarse sand. These benefit the soils, making them warmer, 
lighter, better drained and aerated than the other adobes. They are, 
however, still compact, sticky, retentive of moisture, heavy and difficult 
to cultivate, and have a tendency to pack and bake. Under modern 
methods of intense cultivation they are adapted to citrus and deciduous 
fruits, berries and truck crops, as they are generally supplied with 
organic matter, and naturally rich in plant food. 

FULLERTON SANDY ADOBE. This name is no longer used. That 
mapped as such in the San Bernardino and Ventura areas has beer 
reclassified as Placentia sandy adobe, and that mapped under this title 
in the Los Angeles and Santa Ana areas has been reclassified as Pla- 
centia loam adobe. 

PLACENTIA SANDY ADOBE. Mapped as Maricopa sandy adobe in 
the Bakersficld area, and as Fullerton sandy adobe in the San Bernar- 
dino and Ventura areas. Red to brown, three to six feet deep. SUB- 
SOIL: Coarse, sandy adobe, shiny smooth sandy loam, decomposed 
granite, decayed sandstone, cemented by iron oxides and hj'drates. 
OCCURS on level to slightly sloping land, slightly dcpresed, on 
undulating hills, not typical of any special physiographic feature 
ORIGIN: From granite in place, colluvial wash from adjacent soils, 
degradation of limestones. CROPS: Alfalfa, grain, some fruit. Gen- 
erally free from harmful accumulations of alkali. 

SAN JOAQUIN SANDY ADOBE. Mapped as San Joaquin red 
adobe in the Fresno area. Bright red, six to ten feet. SUBSOIL: 
Same but heavier, liardpan. ORIGIN; From the foothill adobe. 
CROPS: Grain. 

SIERRA SANDY ADOBE. Mapped as Sierra adobe in the Los 
Angeles area. Reddish brown, medium to fine texture, one to three 



Sandy Adobes 135 

feet deep SUBSOIL: Dark red, loam, gravelly loam, granite sand. 
OCCURS on sloping plains. ORIGIN: Composed mainly of granitic 
material deposited in Tertiary or earlier times. During the ear y 
Pleistocene elevation of the land, the material was raised considerably 
above its former level, and since then has been subjected to greater 
wash and weathering. The red color is doubtless due to the oxidation 
of the iron. CROPS: Dry farmed, citrus, deciduous fruits, berries, 
and truck, around Los Angeles. 

GRAVELLY LOAMS 

Fine Coarse Medium Fine Veryflne 
gravel sand sand sand sand Silt <-iay 

Anderson 5 4 10 5 6 4 2., 8. 37 5 « 

?nX'"^ ■.■-:;:::. : : ^ m \ii ,]■} 'li 

Maricopa 11.4 13.1 8.4 19.9 14 » ^^ g 

Oxnard 0.9 1.6 1.3 b.9 lo ^4.2 

Redding.. 4.9 8.3 4.8 li.u i^ ^3^2 



San Joaquin .... 7.2 



its i.2 12.9 8.6 36.0 



TTT 14 8 lis 39.4 14.8 53.8 24.2 

Highest 11.4 14.8 ll.« ^9.* ^^ ^^ 

Lowest 0.9 1.6 l.rf ^-^ 32 g 14.8 

Average 5.7 9.9 d.o 

If soil contains from twenty to fifty per cent of silt and clay, they 
are called gravelly loams, if they contain over fifty percent of fine sand 
and gravel or over twenty-five per cent of fine gravel, coarse and me- 
dium sand Th?se soils consist of sharp angular to water worn gravels 
mTx™d with coarse and medium sands, The texture varies from loose 
o compact according to the proportion of gravel present. They are 
oose and porous to moderately heavy, and take water easily, but are 
not retentive of it. Naturally well drained, they dry quickly. They 
are friabk when cultivated and maintain an excellent tilth Jhe coarse 
gravel gives them warmth, and they cool more slowly at night. 
ANDERSON GRAVELLY LOAM. Mapped in the Redding area. 
Moderately heavy, light red, eight to twelve /"^hes^ SUBSOIL. 
Deeper red, six feet or more, stream gravels, medmni hardpam 
CROPS: Used mainly for grazing; adapted to peaches and grapes if 
well cultivated and irrigated. 

ARBUCKLE GRAVELLY LOAM. Mapped in the Woodland area. 
Gray brown, not analyzed. SUBSOIL: Brown loam clay loam. 
OCCURS- Slopes bordering streams, broad undulatmg areas. 
ORIGIN Due to the coarser material transported by streams crossmg 
the plains. CROPS: Raisin grapes, fruit trees, general farm crops 
when irrigated. 

CORNING GRAVELLY LOAM. Mapped in the Red Bluff area. 
Light red to yellowish red, medium texture, carries g^^^Y/^boggy when 
wet comoact when dry; twelve to twenty inches. SUBSOIL. Kea, 
compact heavyTlay or cky loam. OCCURS on sharply rolling ground, 
hoQ- wallows ORIGIN: Wash from Red Bluff formation. CROF. 
Grlzfug; under irrigation adapted to peaches, almonds, grapes, figs. 
olives. 



136 Soils of California 

INDIO GRAVELLY LOAM. Mapped as Imperial gravelly loam in 
the Imperial area. Consists of gravel composed of agate, quartz, chert, 
flint, limestone, granite, obsidian, and indurated clays, in size from a 
fraction of an inch to five or six inches, six feet or more deep. SUB- 
SOIL: Same with more clay. OCCURS: From the old Beach Line to 
125 feet below sea level. ORIGIN: Derived from granitic rocks 
mingled with some shale and sandstone material, and are formed by 
colluvial and alluvial wash from intermittent or torrential streams, 
wave action, torrents from mountains. CROPS: Valuable for fruits 
suitable for the climate, where they can be irrigated. Little alkali 
except in low places. 

MARICOPA GRAVELLY LOAM. Mapped as Arroyo Seco sandy 
loam in the San Jose and Lower Salinas areas. Mapped as San Gabriel 
gravelly loam in the San Gabriel and Ventura areas. That mapped as 
Maricopa gravelly loam in the Los Angeles area has been reclassified 
as Maricopa fine sandy loam. Dark brown to black, locally yellowish, 
sharp angular gravel, five to six feet deep. SUBSOIL: Sandy gravel. 
OCCURS: On intermediate and upper slopes of valleys, base of abrupt 
slopes along the lower edges of the mountains, comparatively level or 
slightly rolling, rolling hills, alluvial fans. ORIGIN: Unassorted creep 
soil from the mountain sides, from granite schists and allied rocks. 
CROPS: Citrus fruits, vines, apricots, peaches, prunes, plums, almonds, 
olives, and other stone fruits, black-eyed beans. 

OXNARD GRAVELLY LOAM. Mapped as Salinas shale loam in 
Ventura and Lower Salinas Valley areas. Brown to gray, simply shale 
ground fine, chalky material, some boulders. SUBSOIL: Oxnard 
loam. OCCURS: On table lands and fans, extending to the valleys as 
a gently sloping plain, at the mouth of deep gullies. ORIGIN: Derived 
from chalk-like siliceous shale, white or red, from Monterey shale 
mixed with other material, carried down by flood waters. CROPS: 
Lima beans, English walnuts, barley, wheat. Free from alkali. 

REDDING GRAVELLY LOAM. Mapped in the Redding area. Red 
to dark red, six to fifteen inches deep, carries small cobbles. SUB- 
SOIL: Heavy, deep, adobe-like loam, hardpan. OCCURS: Uplands, 
gently rolling. ORIGIN from early Pleistocene alluvium. CROPS: 
Depends upon the nearness of the hardpan to the surface; peaches, 
vines, grapes, strawberries; orchards if hardpan is dynamited. Free 
from alkali. 

SAN JOAQUIN GRAVELLY LOAM. Mapped in the Colusa and 
Marysville areas, deep red to j'^ellowish red, twelve inches to six feet 
deep. SU^BSOIL: Deep red, heavy, dense loam or clay loam. 
OCCURS: On rolling plains, and slopes of lower foothills, marked by 
hog-wallow mounds and knolls. ORIGIN: Alluvial and lacustrine 
deposit, derived from the Red Bluff formation (Pleistocene). CROPS: 
Grazing, dry farming to grain when drained; with intense cultivation, 
adapted to fruits and vines. 

TEHAMA GRAVELLY LOAM. Mapped in the Red Bluflf area. 
Yellow brown to red gray. Compact to hard on drying, carries angular 
rock fragments, eighteen to seventy-two inches. OCCURS: On bor- 



Sandt Adobes 137 

dering intermittent streams, and as terraces and benches. ORIGIN: 
Wash from higher lying soils, well drained. CROP: Grain; under 
irrigation adapted to peaches, berries, almonds, apricots, melons, 
alfalfa. 

GRAVELLY FINE SANDY LOAM 

Fine Coar.se Medium Fine Very fine 

gravel sand sand sand sand Silt Clay 

Elder 3.0 7.6 9.6 38.6 11.8 23.4 5.9 

Mocho 2.7 7.1 6.3 24.9 28.7 23.2 7.2 

Vina 1.9 3.6 4.6 17.7 24.6 21.6 25.5 

Average 2.5 6.1 6.8 27.0 21.7 22.7 12.9 

ELDER GRAVELLY FINE SANDY LOAM. Mapped in the Red 
BlufiF area. Gray, very variable in texture, porous, leachy, eighteen to 
seventy-two inches. SUBSOIL: Sands and silts. OCCURS as 
alluvial stream bottoms, overflowed, limited areas. VEGETATION: 
Underbrush and tree growth. CROP: Pasture. 

MOCHO GRAVELLY FINE SANDY LOAM. Mapped in the Liver- 
more area. Brown, gray, gray yellow, ten to thirty-six inches. SUB- 
SOIL: Coarse gravel. OCCURS: Base of hills, marked by abandoned 
stream channels. ORIGIN: Alluvial. VEGETATION: Sycamore 
trees. CROP: Grazing; adapted to truck and small fruit. 

VINA GRAVELLY FINE SANDY LOAM. Mapped in the Red Bluff 
area. Brown, variable texture, twenty to thirty inches. SUBSOIL: 
Cobbles and volcanic materials. OCCURS on valley plains, surface 
strewn with angular volcanic cobbles and boulders. ORIGIN: 
Reworked product of the Tuscan soil. CROP: Grazing, grain. 

STONY SANDY LOAM 

TUSCAN STONY SANDY LOAM. Mapped in the Red Bluflf area. 
Reddish to reddish brown; covered with boulders of volcanic material, 
three to twelve inches. SUBSOIL: Cemented water-worn gravel. 
OCCURS on land covered by recent volcanic flows. ORIGIN: Resi- 
dual from lava. CROP: Non-agricultural except in small favored 
areas. PHYSICAL ANALYSIS: Fine gravel 7.4, coarse sand 14.7, 
medium sand 7.9, fine sand 11.7, very fine sand 16.9, silt 28.9, clay 12.3. 

GRAVELLY SANDY LOAMS 

Fine Coarse Medium Fine Very line 

gravel sand sand sand sand Silt Clay 

Arbuckle 9.2 12.1 9.1 22.9 16.1 22.4 7.7 

Llvermore 10.1 10.5 6.7 12.0 11.7 36.8 12.2 

Maywood 12.9 11.8 6.2 15.9 12.7 31.6 8.6 

Pleasanton 8.5 11.5 7.2 12.9 13.8 32.1 14.1 

Sacramento ....11.1 20.6 11.9 19.4 11.8 18.7 6.3 

San Joaquin 6.6 17.7 9.0 13.1 8.8 31.9 12.9 

Sites 4.1 8.8 6.7 18.1 18.6 31.8 12.0 

Highest 12.9 20.6 11.9 22.9 18.6 36.8 14.1 

Lowest 4.1 8.8 6.2 12.0 8.8 18.7 6.3 

Average 8.9 13.2 8.1 16.3 13.3 29.3 10.5 

These soils, as the name indicates, contain large proportions of 



138 Soils of California 

the coarsest sands, and very little silt and clay, and are consequently 
light, open, porous, and not retentive of water. 

ARBUCKLE GRAVELLY SANDY LOAM. Mapped in the Wood- 
land area. Gray to j^ellow brown, reddish brown to pink when wet, 
four feet deep, boggy in wet weather. SUBSOIL: Gravelly clay loam, 
gravelly clay. OCCURS: As narrow ridges along old stream beds, on 
broad uniform slopes. ORIGIN: Alluvial. CROPS: Grape vineyards, 
fruits. 

LIVERMORE GRAVELLY SANDY LOAM. Mapped in the Liver- 
more area. Dark brown, contains angular fragments of a great variety 
of rocks, two to three feet. SUBSOIL: Same as soil, lighter in color, 
coarser. OCCURS on benches along creeks. ORIGIN: Colluvial and 
alluvial. VEGETATION: Valley oak, burr clover, alfilaria. CROP: 
Hay, grain. 

MAYWOOD GRAVELLY SANDY LOAM. Mapped in the Red 
Bluff area. Gray brown, carries gravel, puddles slightlv when wet, six 
feet. SUBSOIL: Gravel to loam. OCCURS: Bordering small inter- 
mittent streams. ORIGIN: Alluvial wash. CROP: Adapted to olives, 
oCcicHcs S-Iislfs. etc 

PLEASANTON GRAVELLY SANDY LOAM. Mapped in the Liver 
more area. Brown, contains angular cobbles, eighteen to thirty inches. 
SUBSOIL: Reddish clav loam. OCCURS on rough hills broken by 
deep ravines. ORIGIN: Sedimentary. VEGETATION: Field oak, 
live oak, buckeve. CROP: Grazing. 

REDDING GRAVELLY SANDY LOAM, flapped in the Red Bluff 
area. Light red to red. sticky, carries medium to large gravel, twelve 
to fourteen inches. SUBSOIL: Red clav loam, underlain by red clay. 
OCCURS on low rolling hills. ORIGIN: A Pleistocene alluvial 
deposit. VEGETATION: Upland oak and manzanita. CROP: Grain, 
drj' farming; with irrigation it is adapted to berries, peaches, alfalfa. 
Drainage poor. 

SACRAMENTO GRAVELLY SANDY LOAM. Mapped in the Red- 
ding and Colusa areas. Light brown to reddish brown, gray, contains 
fragments of volcanic and metamorphic rocks. ORIGIN: From rocks 
of volcanic and metamorphic origin; light to slightlv sticky, two to 
six feet deep. SUBSOIL: Cobbles, gravel. OCCURS in irregular 
bodies, long narrow strips, in gulches and ravines, across valley slopes, 
marking the course of former streams, mixed with finer sediments. 
CROPS: Peaches, fruit, grains, 

SAN JOAQUIN GRAVELLY SANDY LOAM. Mapped in the 
Madera area. Dark red, two to six feet. SUBSOIL: Hardpan. 
OCCURS as pronounced ridges on plains. ORIGIN: Reworked 
lacustrine material. CROP: Grain, grapes, figs, olives, probably citrus. 
SITES GRAVELLY SANDY LOAM. Mapped in the Woodland 
area. Yellow to red brown, heavy, well drained, fourteen to thirty 
inches. SUBSOIL: Brown to red gravelly loam, heavy sandy loam, 
weathered conglomerate or shale. OCCURS: Rolling, undulating, 
knolls, and low hills. ORIGIN: Coarser grades of material from wash 
or assorting action of water. CROPS: Grain, pasture, almonds, apri- 
cots, grapes. 



CHAPTER XIX 
FINE SANDY LOAMS 

SANDY LOAMS. SILTY FINE SANDY LOAMS. 

GRAVELLY SAND. GRAVEL. COARSE 

SANDY LOAMS. LOAMY COARSE 

SAND. COARSE SAND. 



Fine Coarse Medium Fine Very fine 

gravel sand sand sand sand Silt Clay 

Anderson 6.4 10.5 6.4 21.9 8.1 37.5 9.9 

Arbuckle 0.4 5.8 10.6 33.3 20.5 17.1 12.1 

Arnold 0.5 2.4 6.7 25.8 32.0 23.5 6.6 

Fresno 0.0 2.4 6.7 25.8 32.0 23.5 6.6 

Gila 0.0 0.5 1.2 16.4 26.2 38.7 16.6 

Hanford 0.7 3.3 3.3 18.1 27.1 35.6 9.2 

Indio 0.0 0.7 1.7 19.4 34.7 25.0 17.7 

Madera 0.4 1.4 3.1 23.5 42.8 18.9 9.6 

Maricopa 2.8 6.3 5.2 19.7 24.9 29.5 11.9 

Maywood 1.8 2.6 2.7 15.1 37.4 30.4 9.6 

Media 1.7 2.5 1.7 12.3 41.6 17.6 22.5 

Mocho 0.0 0.2 1.0 21.0 26.0 41.5 10.0 

Oriand 0.4 2.7 5.2 23.7 21.5 33.5 11.8 

Oxnard 1.6 5.7 7.2 32.3 19.2 24.8 8.9 

Pajaro 0.0 0.0 0.3 30.0 22.9 38.2 8.4 

Placentia 4.2 8.0 7.0 19.1 19.6 28.3 12.1 

Poplar 0.6 4.4 3.6 24.7 19.2 38.6 8.7 

Sacramento .... 0.0 0.3 0.5 32.7 24.0 31.2 8.1 

San Joaquin 1.0 7.8 7.7 25.3 16.3 27.2 14.4 

Santiago 1.7 4.8 5.3 25.9 26.9 26.7 6.6 

Stockton 1.0 3.4 11.4 22.6 24.3 22.8 10.8 

Ulmar 0.4 6.0 4.8 20.7 21.0 32.9 10.0 

Vina 0.5 2.6 5.7 27.1 33.8 22.1 7.8 

Yolo 0.2 1.2 2.2 25.2 36.3 23.3 11.6 

Higiiest 5.4 10.5 11.4 33.3 42.8 41.5 22.5 

Lowest 0.0 0.0 0.3 12.3 8.1 17.1 6.6 

Average 1.0 3.2 4.6 23.4 26.6 28.7 10.4 

If soils contain from twenty to fifty per cent of silt and sand they 
are called fine sandy loam, if they contain over fifty per cent of fine 
sand, or less than twenty-five per cent of fine gravel, coarse and 
medium sand. 

They are the most important soils of the state on account of the 
variety, yield and value of intensively cultivated crops, and are adapted 
to any crop suited to the local and climatic conditions. They are 
smooth, loose, porous, light and friable, and generally well drained on 
account of their texture giving ready percolation. They possess strong 
capillary power and are moderately rententive of moisture under culti- 
vation, but are sometimes sticky when too wet, packing some and hav- 
ing a tendency to puddle. At first they were used only for grazing and 
dry farming; later, alfalfa, barley, wheat, potatoes, etc., were planted 



140 Soils of Califobnia 

extensively; but they are now noted for their special crops, under irri- 
gation and intensive cultivation, of citrus, olives, walnuts, peaches, 
pears, wine and raisin grapes, hops, asparagus, sugar beets, melons, 
strawberries, peanuts, etc., etc. 

ANDERSON FINE SANDY LOAM. Mapped in the Redding area. 
Light red to reddish gray, three to six feet. SUBSOIL: River sands, 
hardpan, clays, volcanic tuflf. CROPS: Adapted to peaches, pears, 
grapes, small fruits, dry farming, grain. 

ARBUCKLE FINE SANDY LOAM. Mapped in the Woodland area. 
Brown, six feet. SUBSOIL: Sandy or silty loam, gravel, yellowish 
brown. OCCURS: Level, well drained. ORIGIN: Alluvial. CROPS: 
Fruit and garden. 

ARNOLD FINE SANDY LOAM. Mapped in the Modesto-Turlock 
area. Chocolate brown, micaceous, contains some gravel, three to 
five feet deep. SUBSOIL: Similar to the soil but heavier. OCCURS 
on the crest of hills, above river terraces. ORIGIN: Alluvial, lacus- 
trine. CROPS: Grain, adapted to fruit, vegetables, grapes. 
FRESNO FINE SANDY LOAM. Mapped in the Indio, Modesto-Tur- 
lock, Madera, and Stockton areas. Mapped as Fresno sandy loam in 
the Fresno area. That mapped as Fresno fine sandy loam in the Bak- 
ersfield, Los Angeles, Lower Salinas Valley, San Bernardino, and San 
Gabriel areas has been reclassified as Hanford fine sandy loam. That 
mapped as Fresno fine sandy loam in the Ventura area has been 
reclassified as Oxnard loam. That mapped as Fresno fine sandy loam 
in the San Jose area has been reclassified as Hanford silt loam. Light 
gray, ashy, fifteen inches to five feet deep. Called "White Ash Land" 
around Fresno. SUBSOIL: White to bluish hardpan. OCCURS: In 
irregular, elongated areas, surface low, flat, or slightly depressed. 
ORIGIN: Derived from white sands, volcanic ash, and granitic 
material. CROPS: Mainly given to grazing, where well drained 
grains, vines and small fruits do well; alfalfa, vines, figs, peaches, ber- 
ries, melons; valuable fruit land around Selma. The alkali in the sub- 
soil makes it sometimes difficult to reclaim the land where the drainage 
is poor. 

GILA FINE SANDY LOAM. Mapped in the Imperial area. Mapped 
as Imperial sandy loam in the Yuma-California area. Reddish brown, 
three to six feet deep. SUBSOIL: Light loam or sandy loam which in 
turn is underlain by loam, clay loam, clay or sand. OCCURS: Level, 
or slightly scored by the wind. ORIGIN: Direct deposit from rivers; 
and sand blown or washed in from the mesas. CROPS: Adapted to 
all the field and fruit crops suitable for the climate. One of the best 
soils in Imperial Valley. Generally free from alkali. 

HANFORD FINE SANDY LOAM. Mapped in the Hanford, Madera 
and Woodland areas. Mapped as Fresno fine sandy loam in the Bak- 
ersfield, Sacramento, Santa Ana, Salinas Valley, San Bernardino, and 
San Gabriel areas. Light to dark gray or drab, brown, bufif, yellowish 
reddish, six feet deep. SUBSOIL: Very variable, often sand. 
OCCURS: In local depressions, near slouughs or drainage basins, on 
the lower terraces and river bottoms subject to overflow, on level delta 



Fine Sandy Loam 141 

plains, adjacent to river and slough channels and tidal flats. ORIGIN: 
From the fine micaceous material derived from granitic, diabasic and 
other fine textured rocks of the foothills and mountains deposited over 
the flood plains from the slack waters of the streams. CROPS 
Among the most important on account of the variety, value, and yield 
adapted to any crops suited to the local climatic conditions; walnuts 
citrus, apples, pears, celery, sugar beets, raisin grapes, hops, asparagus, 
alfalfa, grain, potatoes, truck. There is rarely enough alkali to exclude 
useful crops. 

INDIO FINE SANDY LOAM. Mapped as Fresno fine sandy loam in 
the Indio area. Slate colored, two to five feet. SUBSOIL: Sandy 
loam, sand. OCCURS: Uniform slopes, from 250 feet below sea level 
to 100 above. ORIGIN: Same as Indio fine sand. CROPS: The best 
for general purposes; melons, sweet potatoes, garden crops, etc. Some 
alkali in spots. 

LIVERMORE FINE SANDY LOAM. Mapped in the Livermore 
area. Brown, variable texture, two feet. SUBSOIL: Yellow sandy 
loam. OCCURS in ridges marking the course of former streams. 
Well drained. ORIGIN: Colluvial and alluvial. CROP: Dry farmed 
to grain a~nd hay. Adapted to small fruit, truck, alfalfa. 
MADERA FINE SANDY LOAM. Mapped in the Madera area. 
Brown, fifty to sixty inches. OCCURS on lowlands bordering streams. 
ORIGIN: Alluvial. CROP: Grain; adapted to alfalfa, grapes, small 
fruit. 

MARICOPA FINE SANDY LOAM. Mapped as Maricopa gravelly 
loam in the Los Angeles area. Dark brown to brown, gravel, pebbles 
and cobbles, three to six feet. SUBSOIL: Waterworn granitic sand, 
gravel and boulders. OCCURS: Level terraces along streams, sloping 
plains. ORIGIN: Granitic material brought from the mountains by 
river and streams. CROPS: Grapes, strawberries, oranges, peaclies, 
apricots, alfalfa, etc. Free from alkali. 

MAYWOOD FINE SANDY LOAM. Mapped in the Red Blufif area. 
Yellowish gray, friable, does not puddle or crack, twenty-four to thirty 
inches. SUBSOIL: Loam or gravelly loam. OCCURS: Bordering 
streams, level, well drained. ORIGIN: Wash from higher soils. 
CROP: Alfalfa, peaches, prunes, apricots, melons, truck. 
MEDIA FINE SANDY LOAM. Mapped in the Madera district. Red, 
two to six feet. SUBSOIL: Clay loam. OCCURS on rolling land. 
ORIGIN: Residual. CROPS: Grain; locally to grapes, figs, olives, 
alfalfa. 

MOCHO FINE SANDY LOAM. Mapped in the Livermore area. 
Brown to gray brown; eighteen to twenty-four inches. OCCURS 
along stream channels. ORIGIN: Alluvial from overflow of creeks in 
flood. CROP: Sugar beets, truck. 

ORLAND FINE SANDY LOAM. Mapped in the Colusa area. Red- 
dish to reddish gray, few inches to three feet deep. SUBSOIL: Under- 
lain by partially weathered sandstone. OCCURS: On elevated foot- 
hill ridges, steep slopes, unirrigable. ORIGIN: Residual, derived from 
sandstone in place. CROPS: Dry farming; grain, grazing, adapted to 



142 Soils of California 

fruits, vegetables, and sugar beets under irrigation. Free from alkali. 
OXNARD FINE SANDY LOAM. Mapped in the San Bernardino 
area. Greenish gra}% micaceous, some gravel, one to two feet deep. 
SUBSOIL: Heavy, sticky, gray sandy loam, or loam. OCCURS: 
Smooth, level. ORIGIN: Wash from incoherent sandstones which 
weather into fantastic shapes locally called "Bad Lands." CROPS: 
Wheat, alfalfa. Alkali where poorly drained. 

PAJARO FINE SANDY LOAM. xVIappcd in the Pajaro area. Brown, 
micaceous, eighteen to seventy two inches. SUBSOIL: Black loam, 
or silt loam. OCCURS along the rivers and creeks. ORIGIN: Allu- 
vial and sedimentary. CROPS: Apples, alfalfa, tomatoes, beans, sugar 
beets, cantaloupes, cucumbers, strawberries, loganberries, blackberries. 
PLACENTIA FINE SANDY LOAM. Mapped as Placentia sandy 
loam in the Los Angeles, Lower Salinas Valley, San Bernardino, San 
Jose, San Gabriel and Santa Ana areas. Reddish brown, brown, red- 
dish yellow, eighteen inches to six feet deep. The Gravelly Phase con- 
tains a high percent of gravel. SUBSOIL: Hardpan, compact loam, 
sandy adobe. OCCURS in large bodies on hills, level to steep, low 
rolling hills, mesas, mountain slopes, coastal plains. ORIGIN: The 
origin of this soil is similar to that of many others and may be used as 
an illustration of the origin of sandy loams in general. The greater 
part has been found in place, but some is due to soil-creep from the 
base of the hills. In the Lower Salinas Valley, bordering the Gavilan 
Range, and Sierra Salinas, it is derived from Jurassic and older rocks 
consisting chiefly of fragments of gneiss, schists and granites, brought 
down and distributed by torrential streams from canyon mouths. In 
the Los Angeles area it is the weathered product of granitic material 
that was transported, as above, in late Tertiary times. These old 
washings of Pleistocene times were elevated by a movement of the 
earth's crust, and have since then been much modified by weathering. 
They have also been wind blown along the coast. In the San Jose 
area the line material has been carried a long distance along the slope 
of the mountains and the alluvial fans, or cones, extending outward 
from canyon mouths. These cones often merge and form broad gently 
sloping mesa lands. Where the sandy loam is the result of the break- 
ing down of sandstone or conglomerate the soil contains gravel and 
assumes a gravelly phase as in the San Gabriel area where the soil 
north of Puente is formed partially from the wash of Walnut Creek, 
which drains a sandstone and shale area, and partially from the wash 
of San Dimas Canyon, which drains a granitic area. CROPS: Citrus 
fruits at Riverside, Redlands, Whittier, La Mirada, Santa Fe Springs, 
Montebello, Pico Heights, Palms, Inglevvood, Gardena, San Dimas, 
and in Orange County, walnuts at Whittier, olives, grapes, truck, ber- 
ries, alfalfa, grain, prunes, peaches, wine grapes, cherries, etc. Gener- 
ally free from alkali. 

POPLAR FINE SANDY LOAM. Mapped in the Portersville area. 
Light brown to bufif, micaceous, two to four feet deep. SUBSOIL: 
Reddish or yellowish brown clay loam. OCCURS: In small irregular 
patches, level. ORIGIN: Alluvial, the subsoil is reworked Pleistocene 
material mixed with recent material. CROPS: Pasturage, dairying, 



Fine Sandy Loam 143 

alfalfa, small fruits, deciduous fruits, truck gardens. Practically free 
from alkali. 

SACRAMENTO FINE SANDY LOAM. Mapped in the Colusa. 
Woodland, Redding, Red Bluff, and Sacramento areas. Light gray to 
dark brown, micaceous, eighteen inches to six feet. SUBSOIL: 
Gravels, sandy loams. OCCURS in irregular, narrow, elongated 
bodies, near stream channels, sloughs, uneven, sloping. ORIGIN: 
Recent alluvial. CROPS: Alfalfa, peaches, prunes, pears, plums; 
melons, hops, potatoes, corn, English walnuts, wheat, barley. 
SAN JOAQUIN FINE SANDY LOAM. Mapped in the Colusa, 
Marysville and Sacramento areas. Light red to buf¥, ten inches to three 
feet. SUBSOIL: Red loam, light brown clay loam, heavy indurated 
clay. OCCURS: In irregular shaped bodies, on undulating and smooth 
valley plains, upper benches of ancient flood plain. ORIGIN: Lacus- 
trine, from Red Bluff formation. CROPS: Grazing, grain; with irri- 
gation adapted to grapes, citrus fruits, stone fruits, berries, Tokay 
grapes, strawberries. 

SANTIAGO FINE SANDY LOAM. Mapped as Santiago sandy 
loam in the Santa Ana area, three to four feet deep. SUBSOIL: Sand 
twelve to thirty feet, sand adobe. OCCURS on the higher elevations, 
uplands, broken country. CROPS: Truck, peanuts, wheat, barley, 
small fruits, oranges and walnuts at Orange and Tustin. 
STOCKTON FINE SANDY LOAM. Mapped as Fancher sandy 
loam in the Fresno area. Red, micaceous, high percent of organic 
matter, six feet deep. SUBSOIL: Same, gravelly. OCCURS along 
foothill streams, around sinks, in low lying tracts. ORIGIN: Result 
of stream deposits. CROPS: Typical raisin soil. Minor spots of 
alkali. 

ULMAR FINE SANDY LOAM. Mapped in the Livermore area. 
Brown, thirty to seventy-two inches. SUBSOIL: Yellow fine sandy 
loam with hardpan at from three to five feet. OCCURS on valley 
floor, marked by old stream channels and some hogwallows. 
ORIGIN: Colluvial and alluvial. VEGETATION: Greasewood, alkali 
heath, salt grass. Some alkali. CROPS: Grazing, hay, grain. 
VINA FINE SANDY LOAM. Mapped in the Red Blufif area. Dark 
grey to gray brown, micaceous, uniform texture, six feet. SUBSOIL: 
Gravel. OCCURS on sloping valley plains, bordering streams, marked 
by old channels, poorly drained. ORIGIN: Alluvial, recent deposit of 
streams. VEGETATION: Oak, willow, grapevines. CROPS: Alfalfa, 
peaches, wine grapes, truck, melons, stone fruits. 

YOLO FINE SANDY LOAM. Mapped in the Woodland area. Light 
brown, contains streaks of sand and thin beds of silt, surface some- 
times contains wind-blown sand, fifteen inches. SUBSOIL: Brown 
sand, sandy loam, loam, silt loam. OCCURS as numerous small 
bodies, sloping or slightly undulating, between creeks, lower bench 
lands. ORIGIN: Recent from the shifting currents of the larger 
creeks during flood periods. CROPS: Alfalfa, vines, grain, peaches, 
apricots, almonds, grapes, prunes, truck gardens, sugar beets, general 
farm crops. 



144 



Soils of Califobnia 



SANDY LOAMS 

Fine Coarse Medium Fine Very fine 

gravel sand sand sand sand Silt Clay 

Arnold 10.2 29.4 10.3 12.4 3.5 24.6 9.6 

Bellavista 0.0 6.6 20.1 44.6 4.8 15.0 7.9 

Contra Costa ... 3.8 19.1 16.3 20.3 8.8 22.7 8.9 

Encina 2.1 13.9 19.7 26.5 13.7 16.7 7.5 

Exeter 4.3 17.1 7.8 17.5 7.3 31.7 14.5 

Fresno 1.1 7.4 6.7 21.0 16.2 35.9 9.9 

Gridley 5.0 20.6 14.2 26.1 8.0 16.0 10.2 

Hanford 7.6 25.1 12.9 34.5 7.1 10.2 3.0 

Imperial 0.0 0.2 0.4 9.3 20.3 47.6 15.4 

Madera 1.7 22.0 18.5 21.1 9.6 19.1 7.9 

Maricopa 10.1 19.0 11.5 21.0 12.4 17.1 8.8 

Media 6.4 12.9 7.3 24.5 25.2 16.5 7.2 

Monterey 0.1 7.0 22.4 35.3 1.7 23.1 10.3 

Oaltdale 5.2 22.1 10.1 21.8 9.1 24.6 7.6 

Oxnard 0.3 2.2 3.4 19.1 26.4 34.2 10.3 

Pajaro 0.1 7.0 16.6 37.1 4.9 24.4 9.3 

Placentia 10.6 13.2 6.7 19.1 20.6 18.9 10.7 

Pleasanton 3.4 9.1 6.9 18.1 20.8 30.6 11.2 

Sacramento . . . . 0.7 14.2 10.1 40.4 11.5 14.6 8.4 

San Joaquin .... 4.0 10.5 10.6 18.2 20.2 23.6 10.9 

Santa Cruz 0.3 17.4 22.5 36.0 3.4 10.0 10.3 

Sheridan 2.5 10.9 8.0 31.0 18.7 16.8 11.2 

Sierra 13.0 23.6 10.0 17.6 7.4 15.0 12.8 

Sites 0.0 6.0 9.4 26.6 11.0 27.6 19.4 

Sutter 4.6 11.5 6.8 24.3 14.4 24.3 14.1 

Watsonville .... 0.1 3.1 4.5 17.5 7.2 55.8 11.3 

Highest 13.0 29.4 22.5 44.6 26.4 55.8 19.4 

Lowest 0.0 0.2 0.4 9.3 1.7 10.0 3.0 

Average 3.7 16.1 12.9 24.7 12.5 23.7 10.2 

When soils contain from twenty to fifty per cent of silt and clay 
they are called sandy loam. If they contain over twenty-five per cent 
of fine gravel, coarse and medium sand, they are light and mellow and 
usually of fine texture, but may vary widely in this respect. They are 
often hard and compact when dry, compact and sticky or plastic, with 
a tendency to pack when wet, but loose and friable under cultivation. 
They take water well but become heavier under irrigation, being 
easily cultivated when handled at the right time; but when too moist 
break up into clods. The drainage depends upon local conditions, and 
they are apt to wash under heavy rains. With thorough artificial 
drainage and plenty of irrigating waters they make a fine soil for fruit 
and general farming, forming a moisture-retaining mulch when culti- 
vated. Only depressed areas incapable of drainage and irrigation are 
of no agricultural importance. 

ARNOLD SANDY LOAM. Mapped in the Modesto-Turlock area. 
Gray to brown, contains coarse granite and quartz sand and pebbles. 
SUBSOIL: Yellowish red, clay, coarse sand and silt. OCCURS: Any 
place in the foothills. ORIGIN: Lacustrine and alluvial. CROPS: 
Dry farming, adapted to grapes, olives, almonds, and figs if properly 
managed. 

BELLAVISTA SANDY LOAM, Mapped in the Redding area. Light 
ash-gray, well drained, one to six feet. SUBSOIL: Adobe-like sandy 
clay, a clay hardpan, volcanic ash and tuff. OCCURS: Occupies gently 
sloping valley plains or lower rolling hill slopes. ORIGIN: From the 



Fine Sandy Loam. 145 

erosion of adjacent beds of volcanic ash and tuflf and the distribution of 
this material with the gravels and soils derived from the uplands. 
CROPS: Of limited acreage and minor agricultural importance. 
CONTRA COSTA SANDY LOAM. Mapped in the Livermore area. 
Brown when wet, yellowish when dry, twelve to sixty inches. SUB- 
SOIL: Bedrock. OCCURS on low broken hills. ORIGIN: Residual 
from coarse grained sandstone and conglomerate. VEGETATION: 
Live oak, field oak. CROP: Grain, hay, adapted to eucalyptus. 
DAULTON SANDY LOAM. Mapped in the Madera area. Grayish 
to dark brown, live to forty-eight inches. SUBSOIL: Metamorphic 
rocks or granite. OCCURS on eroded steep rolling lands or foothills. 
ORIGIN: Residual. CROPS: Grazing. 

ENCINA SANDY LOAM. Mapped in the Pajaro area. Drab gray 
to dark brown, coarse, sharp fragments of granite, quartz and shale, 
two feet. SUBSOIL: Gray heavy sandy loam, sandy adobe. 
OCCURS: Slopes of the foothills. ORIGIN: Residual. CROPS: 
Grapes, apples, apricots. 

EXETER SANDY LOAM. Mapped in the Portersville area. Dark to 

reddish brown, fine gravel, drainage good, six feet. SUBSOIL: Simi- 
lar but more compact. OCCURS: Level. ORIGIN: Wash from the 
adjacent soils, recent alluvial. CROPS: Grain, citrus fruits, grapes, 
peaches. Free from alkali. 

FRESNO SANDY LOAM. Mapped in the Hanford and Modesto- 
Turlock areas. That mapped as Fresno sandy loam in the Fresno area 
is Fresno fine sandy loam. That in the Indio area is Indio fine sand, 
called "White Ash Land" in many parts of the San Joaquin Valley. 
White to gray, fine ash, two to three feet. SUBSOIL: Lime-mag- 
nesium hardpan, contains salt and alkali. OCCURS: In irregular- 
shaped bodies. ORIGIN: Derived from white sands, volcanic ash, 
and granitic material. CROPS: With thorough artificial drainage and 
plenty of irrigating water makes a fine soil for fruit and general farm- 
ing; grain, alfalfa, figs, peaches, olives, berries, vines, melons, vege- 
tables, etc. Alkali in depressed areas. 

GRIDLEY SANDY LOAM. Mapped in the Marysville area. Red- 
dish brown, contains waterworn gravel, thirty inches to six feet, drain- 
age good. SUBSOIL: Dark brown sticky loam. OCCURS: Level to 
slightly rolling. ORIGIN: Sedimentary, reworked by later alluvial 
agencies. CROPS: Pasture, grain, peaches, grapes, alfalfa, berries. 

HANFORD SANDY LOAM. Mapped in the Madera and Porters- 
ville area. Mapped as Fancher sandy loam in the Hanford area, gray 
to buflf, six feet. SUBSOIL: Yellow or sticky loam. OCCURS in 
elongated irregular bodies, level or uniform surface, along streams, 
delta plains, coastal plains, lower terraces, valley floors. ORIGIN: 
Alluvial, granitic material from the mountains reworked and deposited 
by streams during floods. CROPS: Alfalfa, grain, deciduous fruits, 
grapes, general utility soil. Traces of alkali. 

IMPERIAL SANDY LOAM. Mapped in the Imperial area. Coarse 
river sediment, three feet. SUBSOIL: Heavy sandy loam, loam. 
OCCURS in large bodies, irregular in form. ORIGIN: Colorado 



146 Soils of California 

River deposits, mixed with wind-blown sand. CROPS: Best for inter- 
tillage crops, fruits, dates, sugar beets, vegetable and general utility. 
Wide range of alkali conditions; some areas free, others badly affected. 
MADERA SANDY LOAM. Mapped in the Madera area. Brown, 
one to six feet. SUBSOIL: Red hardpan. OCCURS on rolling or 
dissected plains, marked by hogwallows. ORIGIN: Reworking of 
older residual soils. CROP: Grain, grazing, local adapted to figs, 
olives, berries, alfalfa. 

MARICOPA SANDY LOAM. Mapped in the Los Angeles area. 
Mapped as San Gabriel sandy loam in the San Bernardino area. Light 
gray to yellowish, brown to reddish, three to six feet. OCCURS on 
hill and mountain slope. ORIGIN: Residual, coUuvial, detritus from 
granite and closely allied rocks. CROPS: Citrus and deciduous fruits, 
peas, beans, tomatoes, egg plant, squashes, potatoes, peppers, pine- 
apples at Hollywood. 

MEDIA SANDY LOAM. Mapped in the Madera area. Red to gray 
red micaceous, carries angular fragments of feldspar, thirty to sixty 
inches. SUBSOIL: Granitic rocks. OCCURS on rolling land cut by 
intermittent stream courses. ORIGIN: Residual. CROP: Grain, 
grazing; local adapted to grapes, figs, olives, alfalfa; possibly to citrus. 
MOCHO SANDY LOAM. Mapped in the Livermore area. Brown 
to gray, frequently consists of alternating strata of silty fine sand, fine 
and coarse sand; three to six feet. SUBSOIL: Brown to black clay, 
clay loam. OCCURS in long narrow strips along stream channels. 
ORIGIN: Alluvial by overflow of creeks. VEGETATION: Syca- 
more, oak, willow. CROPS: Peas, potatoes, cabbages, truck. 
MONTEREY SANDY LOAM. Mapped in Pajaro area. Brown, 
darkened by humus, thirty inches. OCCURS: Broken, hilly, exposed 
slopes, ridges of the foothills of the Coast Range. ORIGIN: From 
the underlying shaly sandstones, and wash from higher ground. 
CROPS: Apricots, orchards where well cultivated. 

OAKDALE SANDY LOAM. Mapped in the Modesto-Turlock area. 
Chocolate brown, micaceous, contains coarse sharp sand, five to six 
feet. SUBSOIL: White hardpan. OCCURS: Smooth, level. 
ORIGIN: Mingling of the material from adjacent soils. CROPS: 
Fine for fruit and general farming; figs, peaches, olives, berries, 
melons, vegetables, etc. 

OXNARD SANDY LOAM. Mapped in the San Bernardino and Ven- 
tura areas. Dark brown to black, light, high in organic matter, drain- 
age poor in places, four to five feet. GRAVELLY PHASE: Contains 
shale gravel. SUBSOIL: Heavy sandy loam, loam, unconsolidated 
sandstones. OCCURS: Level, slightly undulating, gentlj' sloping 
plains, deltas, capping unconsolidated sandstones. ORIGIN: Wash 
from shale and sandstones. CROPS: Sugar beets, grain, truck crops, 
lima beans. May contain small amounts of alkali, rarely 0.20 per cent. 
PAJARO SANDY LOAM. Mapped in the Pajaro area. Dark brown, 
easily tilled, six feet. SUBSOIL: Lighter in color and texture. 
CROPS: Excellent orchard soil, apples, cherries, prunes, plums, pears, 
walnuts, strawberries, raspberries, loganberries, blackberries, when 
irrigated. 



Fine Sandy Loam 147 

PLACENTIA SANDY LOAM. Mapped in the Bakersfield area. 
Mapped as Placentia loam in the Ventura area. Mapped as Placentia 
coarse sandy loam in the San Bernardino area. That mapped as Placen- 
tia sandy loam in the San Bernardino, Los Angeles, San Jose, San Ga- 
briel, Santa Ana, and Lower Salinas Valley area has been reclassified as 
Placentia fine sandy loam. Coarse, compact, well drained, three to 
four feet. SUBSOIL: Red, heavy, coarse and hard sandy loam. 
OCCURS: On the gentle slopes from the foothills. ORIGIN: Col- 
luvial, from waste of the foothills. CROPS: Alfalfa, local small 
orchards. Usually free from harmful accumulations of alkali. 
PLEASANTON SANDY LOAM. Mapped in the Livermore area. 
Reddish brown, sticky; forms a surface crust after rains. OCCURS at 
base of eastern slope of the Coast Range; level to rolling, limited. 
ORIGIN: Sedimentary. CROP: Dry farmed to hay, grain, grapes. 
SACRAMENTO SANDY LOAM. Mapped in the Modesto-Turlock 
area. Brown, gray, micaceous, six feet. SUBSOIL: Coarse sand or 
gravel. OCCURS: Comparatively level, along rivers. ORIGIN: 
Deposited during recent overflows. CROPS: Orchards, gardens, 
truck gardening, berries, melons. 

SAN JOAQUIN SANDY LOAM. Mapped in the Stockton, Sacra- 
mento, Marysville, Madera, Fresno, Modesto-Turlock, and Porters- 
villa areas. Light red, silty, drainage variable, eighteen inches to six 
feet. SUBSOIL: Fine dense hardpan, red, yellow, heavy compact gray 
sandy adobe; sandstone, hardpan. OCCURS: On gentle slopes, flood 
plains, valley floors, on hogwallow land. ORIGIN: Pleistocene lake 
deposits modified by alluvial wash, from adjacent granitic, volcanic 
and metamorphic rocks washed into the Pleistocene lake or bay. 
CROPS: Vary widely locally; hay, oats, barley, rye, peaches, cherries, 
plums, citrus fruits, Zinfandel, Tokay, Emperor, and seedless grapes. 
Alkali not present in injurious quuantities. 

SAN JOAQUIN SANDY LOAM. Mapped in the Madera area. Red 
to yellow brown, eighteen to seventytwo inches. SUBSOIL: Red fer- 
ruginous hardpan. OCCURS on plains marked by hogwallows, poorly 
drained. ORIGIN: Lacustrine. CROP: Grain, figs, olives, grapes. 
SANTA CRUZ SANDY LOAM. Mapped in the Pajaro area. Dark 
red, red brown, two to three feet, high iron contents. SUBSOIL: 
Heavy reddish sandy loam. OCCURS: Steep hillsides. ORIGIN: 
From sandstones in place. CROPS: Apples, wine grapes. The "red- 
wood soils" produce the best orchards. 

SHERIDAN SANDY LOAM. Mapped in the Sacramento area. 
Black, micaceous, drainage variable, six inches to six feet. SUBSOIL: 
Granitic, stream gravels. OCCURS: Lower valley slopes of the foot 
hills. ORIGIN:' Residual or colluvial from the weathering of dark 
colored, fine textured gabbrodiorite and grannodiorite. CROPS: When 
well drained adapted to grains, hay, forage crops, fruit. 

SIERRA SANDY LOAM. Mapped in the Sacramento area. Light 
gray to red, coarse, well drained, three to six feet. OCCURS: Covers 
the rolling, dome-like slopes of the lower foothills, rock outcrops. 
ORIGIN: Disintegration in place of grannodiorite rock. CROPS: 



148 Soils of California 

Berries, vines, citrus fruits, deciduous fruits, peaches, plums, cherries, 
apricots, pears, strawberries, etc., according to local climate. No 
injurious amount of alkali. 

SITES SANDY LOAM. Mapped in the Colusa area. Light red to 
reddish gray, well drained, three to six feet. SUBSOIL: Sandstone. 
OCCURS: Elevated foothill ridges, broken, outcrops of sandstones. 
ORIGIN: Residual from sandstone in place. CROPS: Grain, grazing. 
Free from alkali. 

SUTTER SANDY LOAM. Mapped in the Marysville area. Brown, 
rarely black, three inches to si.\ feet. SUBSOIL: Yellow, brown, 
sticky. OCCURS: In irregular areas, around the edges of buttes, in 
small valleys and coves; occasionally overflowed by backwaters. 
ORIGIN: Largely colluvial, altered by flood material, weathered andes- 
itic rocks, tuffs, breccias. CROPS: Grain, alfalfa, almonds, peaches, 
berries, melons. Free from alkali. 

WATSONVILLE SANDY LOAM. Mapped in the Pajaro area. Red- 
dish brown, sharp angular sand, thirty inches to six feet, high in iron 
salts, drainage good. SUBSOIL: Dark red, heavy sandy loam, sandy 
shales, heavy silty clay loams. OCCURS: Uplands, lower portions of 
Coast Range. ORIGIN: Residual, from underlying shales and con- 
glomerates. CROPS: Grain, apples, apricots, grapes, eucalyptus. 

SILTY FINE SANDY LOAM 

LIVERMORE SILTY FINE SANDY LOAM. Mapped in the Liver- 
more area. Brown, thirty-si.\ inches. SUBSOIL: Yellowish sandy 
loam. OCCURS on level to slightly rolling land with ridges, and for- 
mer stream channels. ORIGIN: Colluvial and alluvial. CROPS: 
Orchard fruits, truck farms, alfalfa. PHYSICAL ANALYSIS: Fine 
gravel 0.0, coarse sand 0.2, medium sand 0.5, fine sand 14.6, very fine 
sand 32.8, silt 41.9, clay 9.9. 

GRAVELLY SAND 
MARICOPA GRAVELLY SAND. Mapped as San Gabriel gravelly 

sand in the San Gabriel area, as Soledad gravelly sand in the Salinas 
area, and as San Gabriel gravelly sand in the San Bernardino area. 
Light to dark gray, yellowish to brown, from fine sand to pieces two 
and three inches in diameter; the fine gravel predominates over all the 
other units; six feet. SUBSOIL: Same as soil, only more compact. 
OCCURS on steep slopes, at foot of mountains. ORIGIN: Granitic 
wash, direct from the mountains. CROPS: Citrus fruits, grapes, 
peaches, apricots. Free from excess of alkali. 

GRAVEL 
HANFORD GRAVEL. Mapped as Fresno gravel in the Sacramento 
area. The true gravel soil is composed of all grades of gravel and 
cobbles, with some small boulders, underlain by the prevailing rock of 
the locality. OCCURS along the lower river benches, on sloping hill- 
sides, and in ravines. ORIGIN: Derived from the rocks of the moun- 
tains and foothills, spread by streams during the flood season. 
CROPS: On account of the impossibility of cultivation, adapted only 
to grazing. 



Fine Sandy Loam 149 

COARSE SANDY LOAMS 

The coarse sandy loams as the name implies, carry large amounts 
of gravel, medium, coarse and fine sands. This gives free movement 
of air and moisture, makes them warm, and light to cultivate. They 
are well drained, loose and incoherent when dry, but s light ly_sticky 
when wet. "s— SS^ 

HANFORD COARSE SANDY LOAM. :\tapped in the Madera area. 
Buff, micaceous, six feet. SUBSOIL: Gravel. Occurs on low ' '^ 
along the San Joaquin River. ORIGIN: From river sediment. 
CROPS: Grain, alfalfa, peaches, grapes, truck. 

MEDIA COARSE SANDY LpAM. Mapped in the Madera area. 
Dark gray, six to forty-eight inches. SUBSOIL: Granitic rocks. 
OCCURS on sharply rounded hills. ORIGIN: Residual. CROPS: 
Grazing, grain. 

OAKDALE COARSE SANDY LOAM. Mapped in the Modesto- 
Turlock area. Chocolate, reddish or yellowish brown, micaceous, 
twelve inches. SUBSOIL: Yellow gray sand loam, free from hard- 
pan. OCCURS: Level land, along rivers. ORIGIN: Alluvial, modi 
fied by old channel material. CROPS: Strawberries, bramble berries, 
almonds, olives, citrus, melons, vegetables. Free from alkali. Physical 
analysis: Fine gravel 13.2, coarse sand 38.8, medium sand 11.1, fine 
sand 14.0, very fine sand 2.7, silt 14.4, clay 5.2. 

PORTERSVILLE COARSE SANDY LOAM. Mapped in the Por 
tersville area. Black, micaceous, one to six feet. SUBSOIL: Granitic 
rocks. OCCURS on lower slopes of the foothills. ORIGIN: Residual 
from the underlying granite, more or less modified by alluvial wash. 
CROPS: Grain; adapted to citrus and deciduous fruits under irrigation. 
PHYSICAL ANALYSIS: Fine gravel 6.4, coarse sand 20.0, medium 
sand 10.3, fine sand 21.5, very fine sand 9.4, silt 22.3, clay 9.9. 

LOAMY COARSE SAND 

In these soils the very fine sand predominates giving the soil a 
loamy character. 

FRESNO LOAMY COARSE SAND, flapped in the Madera area. 
Brown to gray, one to six feet. SUBSOIL: Bluish hardpan. OCCURS 
on lower plains, and in swampy ground. ORIGIN: From former and 
present sloughs, modified by surface erosion. Drainage poor. CROPS: 
Alfalfa, grapes, adapted to peaches, figs, olives, and small fruit where 
it can be drained. PHYSICAL ANALYSIS: Fine gravel 8.1. coarse 
sand 22.3, medium sand 12.7, fine sand 21.7, very fine sand 25.8, silt 5.6. 
clay 3.8. 

COARSE SAND 

Fine Coarse Medium Fine Very fine 

gravel sand sand sand sand Silt Clay 

Fresno 12.0 29.7 18.4 23.6 8.8 4.3 3.1 

Hanford 10.0 28.7 16.4 19.6 8.2 12.2 4.8 

Madera 10.7 25.6 15.3 21.1 12.8 6.9 7.6 

Average 10.9 28.0 16.7 21.4 6.6 7.8 5.1 



150 Soils of California 

FRESNO COARSE SAND. Mapped in the Madera area. Gray to 
yellow gray, six feet. SUBSOIL: Brown sand. OCCURS on valley 
plain, marked by old water courses. ORIGIN: Alluvial. CROPS: 
Adapted to peaches, vines, alfalfa. 

HANFORD COARSE SAND. Mapped in the Madera area. Brown 
to gray brown, micaceous, six feet. SUBSOIL: Same or finer material. 
OCCURS: Along old river channels. ORIGIN: Alluvial, from flood 
of present streams. CROPS: Adapted to alfalfa. 

MADERA COARSE SAND. Mapped in the Madera area. Brown, 
micaceous, four to six feet. SUBSOIL: Red hardpan. OCCURS: As 
narrow bodies following the meandering of streams, as knolls and 
ridges between streams. ORIGIN: Reworking of the original hardpan. 
CROP: Grain. 



CHAPTER XX 

FINE SANDS 

RIVER WASH AND ROCK OUTCROP. ROUGH 

STONY LAND. PEAT. MUCK. LAKE AND 

MARSH. MEADOW SAND. DUNE SAND. 

Fine Coarse Medium Fine Very fine 

gravel sand sand sand sand Silt Clay 

Fresno 1.5 8.5 8.2 37.3 22.0 17.6 5.5 

Hanford 0.0 1.2 4.8 33.3 32.1 21.3 3.8 

Indio 0.1 0.5 2.8 27.7 51.3 13.7 3.1 

Sacramento 0.1 1.0 2.9 59.1 20.6 14.0 2.9 

Highest 1.5 8.5 8.2 59.1 51.3 21.3 5.5 

Lowest 0.0 0.5 2.8 27.7 20.6 13.7 2.9 

Average 0.4 2.8 4.7 39.3 31.5 16.4 3.8 

Soils that contain less than twenty per cent of silt and clay are 
called fine sand, if they contain more than fifty per cent of fine sands, 
or less than twenty-five per cent of fine gravel, coarse and medium 
sand. These soils are generally micaceous, light, smooth, open, porous, 
friable, incoherent and well drained, unless the water table is locally 
high. They are not retentive of moisture, and are easily cultivated. 
FRESNO FINE SAND. Mapped in the Modesto-Turlock and Stock- 
ton areas. That mapped as Fresno fine sand in the Los Angeles and 
Bakersfield areas has been reclassified as Hanford fine sand. That 
mapped as Fresno fine sand in the Indio area has been reclassified as 
Indio fine sandy loam. That classified as Fresno fine sand in the Sac- 
ramento area has been reclassified as Hanford fine sandy loam. Light 
yellow, light brown, gray brown, three to six feet. SUBSOIL: Similar, 
heavier, tenacious when wet. OCCURS: In long narrow areas, gen- 
erally level. ORIGIN: Micaceous granitic material predominates. 
CROPS: When irrigated, adapted to alfalfa, forage, hard fruits, vines, 
etc., requiring a loose, well drained soil. The alkali in the subsoil is 
not injurious when the land is well drained. 

HANFORD FINE SAND. Mapped in the Hanford, Lower Salinas 
Valley and Madera areas. Mapped as Fresno fine sand in the Bakers- 
field and Los Angeles areas. Yellowish, well drained, three to six feet. 
SUBSOIL: Fine sand, loam, sandy loam. OCCURS: On delta plains, 
slightly elevated ridges, lower valley floors, river terraces, along for- 
mer stream channels, level, in irregular shaped bodies. ORIGIN: 
Sedimentary deposits, originally derived from the disintegration of 
granitic rocks, deposited by local streams, carried by currents of mod- 
erate velocity and deposited in slack waters. CROPS: Truck, alfalfa, 
fruit. Some alkali in the surface foot where the land has not been 
cultivated or irrigated. 



152 Soils of Califobnia 

INDIO FINE SAND. Mapped as Fresno sandy loam in the Indio 
area. Grayish, poorly drained, high water table, three to six feet. 
SUBSOIL: Coarse sand. OCCURS: On the slopes below the Indio 
sand, full of blowouts, small dunes, and shallow depressions. ORIGIN: 
Derived from the wash from the mountains and deposited under the 
waters of the basin when it was an arm of the sea. CROPS: Where it 
is not too alkaline will produce any crops adapted to the climate. 
ORLAND FINE SAND. Mapped in the Colusa area. Dark drab, six- 
inches to three feet. SUBSOIL: River sands and gravel. OCCURS: 
In small bodies in bottom lands, a little above stream channels. 
ORIGIN: Recent stream deposits. CROPS: Dry farming, grain, hay, 
pasture. Generally free from alkali. Not analyzed. 
SACRAMENTO FINE SAND. Mapped in the Marysville and Wood- 
land areas. Brown, yellow, buff, variable in texture, six to eighteen 
inches. SUBSOIL: Silty, loamy or coarser sand material. OCCURS: 
On higher elevations approaching the river. ORIGIN: Alluvial. 
CROPS: Garden truck, small fruits. 

SAND 

Fine Coarse Medium Fine Very fine 

gravel sand sand sand sand Silt Clay 

Fresno 2.1 16.8 22.0 25.8 18.7 11.1 ^.0 

Hanford 5.1 14.6 15.5 32.5 16.6 7.9 3.7 

Imperial 0.0 18.0 21.9 34.1 24.1 0.2 1.7 

Madera 1.5 21.4 25.7 27.6 9.5 9.4 4.2 

Maricopa 2.4 13.5 26.6 33.9 15.8 4.9 2.8 

Oakdale 0.0 11.3 25.8 45.5 5.3 8.9 2.2 

Oxnard 0.7 8.6 22.5 32.4 16.2 11.3 6.2 

Sacramento 0.0 3.1 30.5 60.0 2.3 2.2 1.0 

San Joaquin 3.6 15.6 23.3 27.9 12.3 8.9 4.8 

Santa Clara 0.0 3.7 22.0 58.0 5.1 4.8 7.0 

Highest 5.1 21.4 30.5 60.0 24.1 11.3 7.0 

Lowest 0.0 3.1 15.5 25.8 2.3 0.2 1.0 

Average 1.5 12.7 23.6 37.8 12.6 7.6 3.7 

The sand soils in the arid regions are as rich as the other soils, 
and when irrigated are recognized as one of the most important soil 
types of the west. They are leachy if the soil grain is large. The finer 
the sand the more valuable the soil as a rule. They are quickly parched 
in dry weather, absorbing little if any moisture from the air. They dry 
out quickly after rain, or irrigation, and can be worked quickly. Thcj' 
are warm and hold heat well, and are best adapted to quick growing 
crops. Soils that contain less than twenty per cent of silt and clay are 
called sand, if they contain more than twenty-five per cent of fine 
gravel and medium sand, and less than fifty per cent of fine sand. 
They vary from fine to medium texture, and are generally micaceous 
and smooth. Light, open, loose, or only slightly coherent, they are 
very porous and friable. They are not retentive of moisture, generally 
well drained and are easily culutivated, as they never clod or bake, 
and there is no danger of puddling. 

FRESNO SAND. Mapped in the Fresno, Hanford. Madera, Modesto- 
Turlock, and Stockton areas. That mapped as Fresno sand in the 
Bakersfield, Sacramento, San Bernardino, San Gabriel, and Santa .Ana 



Fine Sands 153 

areas has been reclassified as Hanford sand. That mapped as Fresno 
sand in the Indio area has been reclassified as Indio sand. White, gray, 
brown, six feet. SUBSOIL: White sandy loam. OCCURS; In strips, 
on uniform sloping plains, in dune-like ridges. ORIGIN: From I he 
"White formation," consisting of interstratified sands, sandy loams, 
and volcanic ash deposits. CROPS: Wherever well drained, peaches, 
grapes, almonds, nectarines, apricots, cherries, olives, alfalfa, sweet 
potatoes, cantaloupes, berries, early truck. Free from harmful quan- 
tities of alkali, and when well drained none need rise from the subsoil. 
HANFORD SAND. Mapped in the Portersville area. Mapped as 
Fresno sand in the Bakersfield, Los Angeles, Lower Salinas Valley, 
Sacramento, San Bernardino, San Gabriel, and Santa Ana areas. Light 
gray to brown, slightly yellowish, medium to coarse, four to twenty 
feet. SUBSOIL: Sand, gravel, local hardpan. OCCURS: On lower 
terraces, level plains, gentle slopes, lower edge of mountain aprons, 
along streams, in slightly depressed areas representing former streams, 
in strips, smooth, level, locally slightly wind-blown. ORIGIN: Recent 
sedimentary deposits, from original granitic material, deposited by 
shifting currents and flood waters of adjacent and former streams. 
CROPS: Adapted to any crop suited to the local climatic conditions; 
to fruits that require well drained soils that can be irrigated during the 
dry season. Planted to truck crops, grains, alfalfa, deciduous fruits, 
raisin grapes, potatoes in the north, wine grapes, peaches, citrons, 
apricots, in the south; the walnut groves of Rivera, Anaheim, Fuller- 
ton, Elmonte and Santa Ana; the oranges and lemons of Covina, and 
Santa Ana; celery of Santa Ana, etc. Generally free from alkali, a few 
spots the exception. 

IMPERIAL SAND. Mapped in the Imperial area. Mapped as Gila 
fine sand, Yuma area. Fine to coarse, organic matter small per cent. 
SUBSOIL: Loam, clay loam, sandy clay, clay. OCCURS: Smooth, 
level, near sandunes. ORIGIN: Same material as sandunes. CROPS: 
One of the best soils in Imperial Valley, suitable for any crops adapted 
to the climate. Practically free from alkali except where underlaid by 
heavy subsoil. 

INDIO SAND. Mapped as Fresno sand in the Indio area. Whitisli 
gray, six feet. SUBSOIL: Same but coarser. OCCURS: Skirting the 
mountains, above present water supply. ORIGIN: Old beach sand 
with material washed down from the mountain. CROPS: Would make 
good soil for fruits, grains and alfalfa. Free from alkali. Not analyzed. 
GRAVELLY PHASE: Grayish white, coarse hard material, six feet or 
more, above the old beach line, alluvial fans and cone deltas, caused by 
storm waters. 

MADERA SAND. Mapped in the Madera area. Brown, three to six 
feet. SUBSOIL: Red hardpan. OCCURS in long narrow bodies 
parallel to shallow water courses on rolling land, marked by hog- 
wallows. ORIGIN: Doubtful — possibly from blowing out of material 
from dry stream courses. CROP: Grain; adapted to alfalfa, grapes, 
figs, olives, stone fruits. 

MARICOPA SAND. Mapped as Fresno sand, gravelly phase, in the 
Ventura area. Light brown to white, gravelly, six feet. SUBSOIL: 
Variable. OCCURS: As long, gentle sloping valleys, floor of small 



154 Soils of California 

washes, next terrace above bottom lands, smooth to steep sloping. 
ORIGIN: Coarsest wash from the hills, by small streams and heavy 
downpours. CROPS: Fruits suited to the climate, lima beans. Free 
from alkali. 

OAKDALE SAND. Mapped in the Modesto-Turlock area. Light 
brown, micaceous, carries silt and clay, six feet. SUBSOIL: Same, 
heavier. OCCLTRS: Along the lower slopes of terraces, smooth, gently 
sloping. ORIGIN: Working over of the Oakdale coarse sandy loam 
by the wind, the finer particles collecting along the lower sides of the 
terraces. CROPS: Almonds; adapted to many crops where irrigated. 
OXNARD SAND. Mapped in the Los Angeles, San Bernardino and 
Ventura areas. Gray to yellowish gray, dark gray, gray brown; may 
grade into indurated sand; number of local phases; six to ten feet. 
SUBSOIL: Same. OCCURS: At the edge of mesas, rolling, undulat- 
ing, in ridges or as dunes, wind-blown, in hills, on deltas. ORIGIN: 
Blown out of the adjacent soils, largely aeolian, beach sand driven 
inland. CROPS: Olives, grains, corn, barley, peas, sugar beets, grapes, 
citrus fruits, berries, truck, flowers. Free from alkali. 
PAJARO SAND. Mapped in the Pajaro area. Light brown, six 
feet. SUBSOIL: Same, heavier. OCCURS: At the junction of streams 
by a rapid rush of large bodies of water. ORIGIN: Alluvial and sedi- 
mentary. CROPS: Fruits, vegetables and grains, when not too wet. 
Not analyzed. 

SACRAMENTO SAND. Mapped in the Red Bluff and Woodland 
areas. Light to dark gray, two to four feet. SUBSOII>: Sand heavier 
texture. OCCURS: Ridges and mounds subject to overflow. ORIGIN: 
Wash from the rivers deposited by rapidly moving waters. CROPS: 
Requires leveling, and protection from floods before using for truck- 
crops. 

SAN JOAQUIN SAND. Mapped as Fresno sand in the Fresno area. 
Mapped as Fresno red sand, Sacramento area. Gray to dark brown, 
six feet. SUBSOIL: Red sandy loam, red sandy adobe, red sandy 
hardpan. OCCURS in irregular shaped bodies, summits of higher 
ridges, undulations and upper valley margins. ORIGIN: From adja- 
cent granitic rocks, intermingled with the wash from diabase, amphib- 
olite and volcanic rocks, ancient Pleistocene lake deposits, weathering 
nf red sandstone formation. CROPS: One of the most important soils 
of the Sacramento area; citrus and stone fruits, figs, peaches, plums, 
prunes, cherries, apricots, olives, nectarines, raisin grapes. Alkali 
not present in harmful quantities. 

SANTA CRUZ SAND. Mapped in the Pajaro area. Light to dark 
red, reddish brown, three to six feet. SUBSOIL: Disintegrated red 
sandstone. OCCURS: Occupies spurs of the mountains. ORIGIN: 
Weathering of red sandstone in place. CROPS: Oats and Indian 
corn, eucalyptus trees. 

DUNESAND. Mapped in the Indio, Imperial. Los Angeles, Pajaro, 
and Ventura areas. Also called coastal sand, beach sand, etc. The 
name "dune" is given to the rounded hills and ridges of wind-blown 
sand common in arid regions and along windy shores. They are nat- 



Fine Sands 155 

urally of moderately fine and uniformly assorted materials as shown 
by an analysis: Fine gravel 0.0, coarse sand 24.7, medium sand 46.3, 
fine sand 25.2, very fine sand 0.8, silt 1.7, and clay 1.6. They are usually 
considered undesirable for agricultural purposes, but they are not infer- 
tile in the sense that they lack the mineral elements of plant food, as 
they contain the ordinary soil minerals and wherever reclaimed have 
proven perfectly capable of supporting agriculturally valuable vegeta- 
tion. The barrenness of the dunesand is due to lack of water and 
instability of surface rather than to any deficiency of mineral plant 
nutrients. Although very absorptive, these sands have very little 
power to retain moisture, and it is generally too expensive to level 
them for irrigating. They are free from alkali or contain only harm- 
less amounts. They are well drained and have a texture favorable for 
cultivation. Many of the choice orchards of Southern California were 
considered a couple of decades ago as worthless sandhills, and now 
serve to show what many so-called dune wastes could become if prop- 
erly handled. The first step is stopping the sand movement and estab- 
lishing a stable and permanent surface. This is done by planting 
grasses which will bind the surface and protect it from attack by the 
wind. Marram or beach grass (Ammophila areparia) has been found 
particularly useful on coastal dunes. Many reclaimed areas are then 
put into forest. The reclamation work at Golden Gate Park, San 
Francisco, shows what may be accomplished with these sands. 

RIVERWASH AND ROCK OUTCROP. Mapped in the Colusa. 
Red Bluff, Redding, Livermore, San Bernardino, Bakersfield, Modesto- 
Turlock, Madera, Sacramento, Los Angeles, Portersville, San Jose, San 
Gabriel, Ventura, Lower Salinas Valley, Fresno, and Woodland areas. 
SOIL: Consists of a mixture of rounded and flattened gravel, cobble- 
stones, sand and finer sediments, the coarser material greatly predom- 
inating, merges into adjacent fine sands and gravelly loams, leachy 
character, six inches to six feet. OCCURS: Occupies beds of portions 
of the flood plains, lower terraces, abandoned and present creek and 
river channels, subject to overflow, low flat sandbars and spits. 
ORIGIN: Recent alluvial, from a great variety of rocks, CROPS: 
Generally barren and of no value except for grazing. 
ROUGH STONY LAND. Mapped in the Colusa. Redding, Porters- 
ville, Sacramento and Yuma-California areas. SOIL: Light red. graj'. 
drab, yellow red, loam or clay loam, friable, carries relatively large 
amount of cobbles, small boulders and gravel, six inches to six feet, 
from bare rock outcrops to sand. SUBSOIL: Yellow, red, clays, 
indurated clay hardpan. volcanic ash, breccias. OCCURS: In narrow 
elongated bodies, bordering stream valleys, higher hilly portions or 
knolls of uplands, rugged hills. ORIGIN: From ancient alluvial 
deposits, from volcanic muds and breccias, residues. CROPS: Grazing. 
PEAT. Mapped in the Los Angeles, San Bernardino, Santa Ana and 
Stockton areas. Dark brown to black; smooth, pasty consistency when 
wet, depth variable, no tendency to puddle, friable, easily cultivated 
when once broken, light weight, poorly drained. SUBSOIL: Sand, 
silts, or sandy clay. OCCUR at river deltas, shallow fresh water lakes, 
former lake beds, near springs. ORIGIN: Formed by the decay of 



156 Soils of Califobnia 



vegetation in shallow lakes, ponds, or swamps; some clay and silt arc 
blown in by the winds or carried in by streams; they contain from 
thirty to ninety per cent of humus; from aquatic plants in various 
stages of decomposition, fine alluvial river or tidal silt intimately 
mixed with partially decayed vegetation, plant routs, stems, and fibres 
in great profusion, or vegetable matter grown and more or less pre- 
served in standing water, growing and decaying tules. CROPS: If the 
vegetable matter is sufficiently decayed and mingled with some minertl 
matter, and the soil is well drained, they yield enormously under favor- 
able conditions, but successive croppings decrease production. Aspara- 
gus, beans, celery, onions, timothy, redtop, rye grass, clover, grains, 
corn, potatoes. Naturally free from alkali. 

MUCK. Muck soils represent the advanced state of change in peat 
areas. They are of limited extent and poorly drained. They are highly 
valued for their adaptation to special crops, such as celery, onions, 
peppermint, etc. 

LAKE AND MARSH SOILS. Mapped in the Bntte Lake area. 
Formed in shallow lakes such as favor the growth of aquatic plants, 
as the tules (Scirpus) and cat-tails (Typha) which form great masses 
of decaying matter, giving to the loamy and sandy soils a friable mucky 
or peaty character. When properly drained they are extremely fertile 
and produce immense crops of timothy, clover, red top, potatoes, cel- 
ery, asparagus, etc. 

MEADOW SOIL. Mapped in the Fresno area. Fine gravel 0.0, 
coarse sand 0.3. medium sand 1.9, fine sand 10.1, very fine sand 45.9, 
silt 31.5, clay 5.3. These soils consist mainly of very fine sand and silt 
with a little clay. They are fine micaceous sandy loams with little true 
clayey matter, and very little coarse sand or gravel, variable in texture, 
color and depth. OCCUR: They comprise lowlying, flat, and poorly 
drained land of variable texture, on the "Meadows" along Kings River, 
along river bottoms. ORIGIN: Sediments dropped by rivers in flood, 
in part material cut from the banks, sorted over, and laid down. 
CROPS: Much of it can be reclaimed by draining, and it is then 
adapted to a variety of crops, pasture, truck, orchards, corn. Alkali is 
occasionally found in a few spots. 



CHAPTER XXI 
HARDPAN. ALKALI. 

Hardpan in the true sense of the word is not bedrock, nor a 
material formed under the water as sedimentary rocks are formed, but 
is a secondary product formed in the soil through local conditions. All 
water which percolates through the soil soon dissolves from it soluble 
materials of dift'erent kinds. A change of temperature, a checking of 
the water movement, or a rapid loss of the contained gases, or other 
causes may precipitate hardpan near the zone of change. It is impene- 
trable to plant roots and limits the root zone of crops; cultivation is 
interrupted, movement of the soil water is arrested, drainage retarded, 
and the power to retain and to deliver water is decreased. Hardpan is 
subject to much variation, even in short distances. It may be exposed 
on the surface where the soil has been subject to erosion, or it may 
occur at any depth below the surface. Where it is thin, easily disin- 
tegrated, low in alkali contents, and easily penetrated by plant roots, it 
is not harmful and may even be beneficial in holding the moisture 
within reach of the plants. 

Where it occurs near the surface or where it is very hard it is 
harmful in several ways. It prevents the deep penetration necessary 
for trees, vines and alfalfa. It restricts drainage, often forming shal- 
low basins of water-saturated soil fatal to plant roots. The excess of 
lime occurring in hardpan is especially injurious to citrus fruits, as 
indicated by the yellowing of the leaves. Indications of hardpan are 
usually seen in hummocky, uneven surface, and small shallow depres- 
sions, the result of deficient drainage. When the hardpan is three or 
four feet below the surface the land may be adapted to vines and other 
shallow rooted growths. Trees require deep soils and hardpan must 
be broken up by blasting where the trees are to be planted. 

ALKALI SOILS 

Lands may carry alkali salts in sufficient quantities to become more 
or less a menace to irrigated crops. These salts are sodium chloride, 
magnesium chloride, calcium chloride, sodium sulfate, magnesium 
sulfate, calcium sulfate, and sodium carbonate. When sodium carbon- 
ate is present, the salt mixture is commonly known as "black alkali," 
because the charring effect of this salt upon organic matter gives a 
characteristic black color to the soil. When sodium carbonate is 
absent, the salts effloresce on the surface as a white powder, or crust, 
called "white alkali." The white alkali is not so injurious to crops, and 
is much more soluble than the black alkali. The greater part of the 
alkalies originate from alkali-bearing shales and other sedimentary 
rocks, especially from those of marine origin. Alkali is confined 
chiefly to the heavier soil types, and normally is more apt to be dis- 
tributed through the subsoils. There is no evidence that there are 
deep seated accumulations of alkali. 



158 Soils of California 

CLASSIFICATION OF ALKALI SOILS. The percent of alkali in 
the soils is determined in the field when the soil maps are made by 
means of the electric resistance of the soil solution, each foot section 
being determined separately, and are also determined volumetrically 
in the field from the total of soluble salts. 

The alkali contents of the soils are graded according to the aver- 
age salt contents to the depth of six feet, as follows: 

No. 1 0. to 0.20 per cent 

" 2 0.20 to 0.40 per cent 

" 3 0.40 to 0.60 per cent 

" 4 0.60 to 1.00 per cent 

" 5 1.00 to 3.00 per cent 

LIMITS OF ENDURANCE. A number of factors enter into the 

limit of endurance of plants for alkali. With the same amount of alkali, 
plants will suffer less in heavier soils than in sandy. Crops will stand 
more alkali with thorough cultivation, and they will stand a consider- 
able amount of alkali if they are started under favorable conditions. 
In some districts sugar beets do well on soils containing a large amount 
of alkali. They are planted when the ground is wet by rains, or irri- 
gation, which carries the alkali into the depths of the soil. When the 
soil dries out the alkali is brought to the surface and is left above 
the area of the active roots. Where the average alkali content is less 
than 0.20 per cent, no injury to crops may be feared under general 
conditions. This is, however, considered the minimum limit of dan- 
ger for ordinary irrigated crops. Many crops can be successfully 
grown where the average concentration is from 0.20 to 0.40 per cent, 
but lands ranging from 0.40 to 0.60 per cent are generally devoted to 
pasture. Over 0.40 by no means takes away the value of the land for 
some agricultural purposes. Some of the hardier fruits, especially 
pears, can be grown under intelligent cultivation. Onions, asparagus, 
and sugar beets, barley, grain or hay, will resist this per cent if the 
ground is well prepared for the seed bed and the salts kept away from 
the tender young roots by frequent irrigation and cultivation. Sorg- 
hum, sugar beets and alfalfa have produced partial to full crops on land 
ranging from 0.40 to 0.60. With black alkali, 0.05 is the minimum of 
concentration beyond which crops begin to suffer. 

Some alkali salts are readily carried into solution and their dis- 
tribution in the soil is determined largely by the movements of soil 
waters. The concentration in lower valley plains and depressions of 
deficient drainage has been caused mainly by evaporation from flood 
waters charged with small quantities of alkali salts leached from the 
higher adjacent soil bodies and from alkali-bearing rocks. Rapid 
evaporation, long periods of hot dry weather, compact, uncultivated 
and unshaded soil surfaces, with water table near the surface tend 
towards concentration of alkali at or near the surface. While the con- 
centration and distribution of alkali in the soil and subsoil depends 
upon a variety of circumstances, it will be found that the main ones 
are — soil texture and structure, position of the underground water 
table, and the rapidity, direction and movement of the soil waters. 
Where soils are subject to overflow and have a high water table there 
is an accumulation of salts at the intervals between floods. Each over- 



Habdpan. Alkali 159 

flow washes the salts out and leaves the soil temporarily free from the 
salts at the surface. These lands are called "intermittent alkali lands." 
The alkali salts are readily dissolved and carried downward and out- 
ward in soils of loose, open texture and structure, by water applied 
in excess of saturation. In soils of fine texture and compact structure 
the salts tend to cling to the finer particles, checking the downward 
movement, hence salts tend to collect near the surface and within the 
root zone of crops. Heavy rains, as well as surface irrigation, soaking 
downward into the soil dissolve and carry the salts downward by grav- 
ity to the limits of penetration. If the surface flooding be copious and 
gravitation movement aided by natural or artificial underdrainage, 
large amounts of the alkali may be permanently removed. As soon as 
the downward movement of flood waters ceases, an upward movement 
begins through capillary action caused by the surface evaporation, 
causing a surface crust of alkali as the waters evaporate. The surface 
should be kept, between the periods of flooding, in a condition of fine 
tilth by cultivation, the mulch of loose earth retarding evaporation and 
the upward movement by capillarity. As soon as the soil is free from 
excess, by underdrainage and occasional flooding, thorough cultivation 
should begin, using alkali-resisting crops which can be cultivated fre- 
quently or which shade the surface, as sorghum, sugar beets or alfalfa. 
In the case of black alkali, the application of gypsum to the surface is 
beneficial, changing the sodium carbonate into the more soluble sodium 
sulfate. 



APPENDIX 



CHANGED SOIL NAMES 

The following list gives the soil names in published reports 
of the U. S. Bureau of Soils that as a result of correlation have 
been changed or dropped. In the first column is given the name 
at present used, in the second column is given the original name. 

Present Name Name as published 

BAKERSFIELD AREA 

Hanf ord sand Fresno sand 

Hanf ord fine sand Fresno fine sand 

Hanford fine sandy loam Fresno fine sandy loam 

Fresno loam Maricopa loam 

Placentia sandy adobe Maricopa sandy adobe 

Hanford clay loam Oxnard silt loam 

Placentia sandy loam Placentia sandy loam 

Riverwasli Riverwash 

Gravelly areas Gravelly areas 

COLUSA AREA 
(No changes in Colusa area yet.) 

Norman clay adobe 

Orland fine sandy loam. 

Orland fine sand. 

Riverwash. 

Rough stony lands. 

Sacramento gravelly sandy loam. 

Sacramento fine sandy loam. 

Sacramento loam. 

Sacramento silt loam. 

Sacramento silty clay loam. 

Sacramento silty clay. 

San Joaquin gravelly loam. 

San Joaquin loam. 

Sites sandy loam. 

Sites loam. 

Sites clay loam adobe. 

Willows loam. 

Willows silty clay loam. 

Willows clay loam. 

Willows clay. 

Willows clay adobe. 

FRESNO AREA 

Stockton fine sandy loam Fancher sandy loam 

San Joaquin sand Fresno red sand 

Fresno fine sandy loam Fresno sandy loam 

San Joaquin sandy loam San Joaquin red adobe 

San Joaquin sandy loam San Joaquin sandy loam 

Stockton clay loam adobe San Joaquin black adobe 

Placentia clay loam adobe Sierra adobe 

Riverwash Riverwash 

Meadow Meadow 



Changed Soil Names 161 

Present Name Name as published 

HANFORD AREA 

Hanford sandy loam Fancher sandy loam 

Fresno sand Fresno sand 

Fresno sandy loam Fresno sandy loam 

Hanford fine sand Hanford fine sand 

Hanford fine sandy loam Hanford fine sandy loam 

Stockton clay loam adobe San Joaquin black adobe 

IMPERIAL AREA 

Gi'a fina sandy loam Gila fine sandy loam 

Dunesand Dunesand 

Imperial sand Imperial sand 

Imperial sandy loam Imperial sandy loam 

Gila loam Imperial fine sandy loam 

Indio gravelly loam Imperial gravelly loam 

Imperial clay loam Imperial loam 

Imperial clay Imperial clay 

Gila silt loam Imperial silt loam 

INDIO AREA 

Dunesand Dunesand 

Tndio sand Fresno sand 

Indio fine sandy loam Fresno fine sandy loam 

Indio fine sand Fresno sandy loam 

Imperial clay Imperial clay 

LOS ANGELES AREA 

Hanford fine sand Fresno fine sand 

Hanford fine sandy loam Fresno fine sandy loam 

Placentia loam adobe Fullerton sandy adobe 

Hanford sand Fresno sand 

Galveston clay Galveston clay 

Placentia loam Los Angeles sandy loam 

Maricopa fine sandy loam Maricopa gravelly loam 

Maricopa sandy loam Maricopa sandy loam 

Oxnard sand Oxnard sand 

Oxnard clay loam Oxnard loam 

Peat . t Peat 

Placentia fine sandy loam Placentia sandy loam 

Hanford loam Santiago silt loam 

Hanford clay loam Santiago silt loam 

Oxnard clay loam adobe San Joaquin black adobe 

Sierra sandy adobe Sierra adobe 

Rlverwash Riverwash 

REDDING AREA 
(No changes in the Redding area.) 
Anderson gravelly loam. 
Anderson fine sandy loam. 
Bellavlsta sandy loam. 
Redding gravelly loam. 

Redding loam. ' 

Riverwash. 
Rough stony land. 
Sacramento gravelly sandy loam. 
Sacramento fine sandy loam. 
Sacramento loam. 
Sacramento silt loam. 

SACRAMENTO AREA 

Hanford sand Fresno sand 

Hanford fine sandy loam Fresno fine sand 

Hanford gravel Fresno gravel 

San Joaquin sand Fresno red sand 

Riverwash Riverwash 

Rock outcrop Rock outcrop 

Rough stony land Rough stony land 



162 Soils of Caui-ornia 

Present Name Name as published 

Hanford silt loam Sacramento silt loam 

Hanford clay adobe Salinas gray adobe 

San Joaquin sandy loam San Joaquin sandy loam 

ban Joaquin fine sandy loam San Joaquin fine sandy loam 

San Joaquin clay loam adobe San Joaquin red adobe 

Sheridan sandy loam Sheridan sandy loam 

blerra stony loam Sierra stony loam 

Sierra sandy loam Sierra sandy loam 

Sierra loam adobe Sierra loam 

Sierra clay loam Sierra clay loam 

SALINAS AREA 

Maricopa gravelly loam Arroyo seco sandv loam 

Hanford fine sandy loam Fresno fine sandy loam 

Hanford sand Fresno sand 

Hanford fine sand Hanford fine sand 

Placentia fine sandy loam Placentia sandy loam 

Riverwash Riverwash 

Salinas gray adobe Salinas gray adobe 

Oxnard gravelly loam Salinas shale loam 

Hanford silt loam Santiago silt loam 

Hanford clay loam Santiago silt loam 

Oxnard clay loam adobe San Joaquin black adobe 

Maricopa gravelly .sand Soledad gravelly sand 

SAN BERNARDINO AREA 

Hanford fine sandy loam Fresno fine sandy loam 

Placentia sandy adobe Fullerton sandy adobe 

Hanford sand Fresno sand 

Maricopa gravelly sand Maricopa gravelly sand 

Maricopa loam Maricopa sandy loam 

Oxnard sand Oxnard sand 

Oxnard .sandy loam Oxnard sandy loam 

Oxnard fine sandy loam Oxnard fine sandy loam 

Oxnard loam Oxnard loam 

Peat Peat 

Placentia fine sandy loam Placentia sandy loam 

Placentia clay loam Placentia loam 

Placentia coarse sandy loam Placentia coarse sandy loam 

Riverwash Riverwash 

Salinas gray adolie Salinas gray adobe 

Hanford clay loam Santiago silt loam 

Maricopa sandy loam San Gabriel sandy loatn 

Maricopa gravelly loam San Gabriel gravelly loam 

Maricopa gravelly sand San Gabriel gravelly sand 

Oxnard clay loam adobe San Joaquin black adobe 

SAN GABRIEL AREA 

Hanford sand Fresno sand 

Hanford fine sandy loam Fresno fine sandy loam 

Placentia fine sandy loam Placentia sandy loam 

Riverwash Riverwash 

Hanford clay loam Santiago silt loam 

Maricopa gravelly loam San Gabriel gravelly loam 

San Gabriel gravelly sand San Gabriel gravelly sand 

Oxnard clay loam adobe San Joaquin black adobe 

SAN JOSE AREA 

Maricopa gravelly loam Arroyo Seco sandy loam 

Hanford silt loam Fresno fine sandy loam 

Galveston clay Galveston clay 

Oxnard clay loam Oxnard loam 

Oxnard silt loam Oxnard silt loam 

Placentia fine sandy loam Placentia sandy loam 

Riverwash o •,•.•• • Riverwash 

Salinas gray adobe • • • • • -Salinas gray adobe 

Stockton clay loam adobe San Joaquin black adobe 



Changed Soil Names 168 

Present Name Name as published 

SANTA ANA AREA 

Hanf ord sand Fresno sand 

Hanford fine sandy loam Fresno fine sandy loam 

Palcentia loam adobe Fullerton sandy adobe 

Peat Peat 

Placentia fine sandy loam Placentia sandy loam 

Oxnard clay loam adobe San Joaquin black adobe 

Santiago fine sandy loam Santiago sandy loam 

Santiago loam Santiago loam 

Hanford clay loam Santiago silt loam 

SOLEDAD AREA 

Placentia sandy loam Placentia sandy loam 

Fresno sand Fresno sand 

Maricopa gravelly sand Soledad gravelly sand 

Maricopa gravelly loam Arroyo Seco sandy loam 

Oxnard gravelly loam Salinas siiale loam 

Salinas gray adobe Salinas gray adobe 

Rivervsrash Riverwash 

Hanford fine sand Hanford fine sand 

Fresno fine sandy loam Fresno fine sandy loam 

Hanford clay loam Santiago silt loam 

STOCKTON AREA 

Stockton fine sandy loam Fancher sandy loam 

Fresno sand Fresno sand 

Fresno fine sand Fresno fine sand 

Fresno sandy loam Fresno sandy loam 

Fresno fine sandy loam Fresno fine sandy loam 

Peat Peat 

Sacramento clay loam Sacramento clay loam 

San Joaquin sandy loam San Joaquin sandy loam 

San Joaquin loam San Joaquin loam 

Stockton loam Stockton loam 

Stockton loam adobe Stockton loam adobe 

Stockton silt loam Stockton silt loam 

Stockton clay loam adobe Stockton clay loam adobe 

Stockton clay adobe Stockton clay adobe 

VENTURA AREA 

Dunesand Dunesand 

Maricopa sand Fresno sand (gravelly phase) 

Oxnard loam Fresno fine sandy loam 

Placentia sandy adobe Fullerton sandy adobe 

Oxnard sand Oxnard sand 

Oxnard sandy loam Oxnard sandy loam 

Oxnard clay loam Oxnard loam 

Oxnard silt loam Oxnard silt loam 

Placentia loam Placentia sandy loam 

Riverwash Riverwash 

Oxnard gravelly loam Salinas shale loam 

Oxnard clay loam adobe San Joaquin black adobe 

Maricopa gravelly loam San Gabriel gravelly loam 

TUMA-CALIFORNIA AREA 

Maricopa sand Fresno gravelly sand 

Gila fine sandy loam Imperial sandy loam 

Gila loam Imperial fine sandy loam 

Gila silt loam. .Santiago silt loam in 1902 map: changed to Imperial 
silt loam 1904. 

Gila clay loam Imperial loam 

Rough stony land Rough stony land 

Imperial sand Imperial sand 



INDEX 



INDEX TO SOIL NAMES 



COMMON NAMES. 

Acid. soil. 47, 81, 83. 
Aeolian, 47. 
Arid. 48, 76. 
Ashy flat, 47. 

Baybusli pocoson, 4S. 
Beecli land. 47. 48. 
Beach sand, 154. 
Beeswax, 48, 52. 
Black alkali land, 53. 
Black gum. 48. 
Black jack, 48. 
Black land, 48, 63, 125. 
Black waxy land, 47. 
Black post oak, 48. 
Black prairie, 48. 
Black walnut, 48. 
Blue grass, 48. 
Boggy land, 47. 
Brier pocoson, 48. 
Buckleberry, 48. 
Buckshot. 48. 
Bugleland, 52. 
Bullnettle, 48. 

Canebrake, 48. 

Cap. 48. 

Cedar, 49. 

Chaffy, 52. 

Chalk, 48. 

Chestnut. 49. 

Chinquapin. 48. 

Chocolate, 48. 

Clay upland, 47. 

Coarse, 47. 

Coastal sand. 154. 

Cold. 48. 

Conowingo barrens, 49. 

Crawfish. 49, 73. 

Crayfish. 49. 

Cumulose,49. 

Cypress, 49. 

Deadland, 49. 
Dead, 87. 
Dilluvial, 49. 
Drybog, 52, 124. 
Drybog adobe. 52. 124. 
Drybog land, 52, 113. 
Dust, 49. 

Endogenous, 49. 
Eolian, 47. 
Exogenous, 49. 



Fine, 49, 63. 
First bottom land, 49. 
Flat pine wood, 49. 
Flat woods, 49. 
Foothill, 52. 122. 

Galled, 49. 
Garden, 49. 
Glacial, 39, 49. 
Glade, 49. 
Glady, 50. 
Granite. 49. 
Grass peat, 49. 
Gray, 49. 
Gray lands, 49. 
Gray prairie, 49. 
Gumbo. 50. 

Hardpan, 104. 
Heavy bottom, 50. 
Hemlock, 50. 
Highland, 47. 
Hogwallow, 60, 110. 
Hogwallow land, 52. 
Humus, 60. 

Isinglass, 50. 

Jack pine, 50. 

Lake front, 60. 
Laterite, 50. 
Limestone. 47. 50. 
Limestone land, 50. 
Loess, 13, 60. 
Looseland, 60. 
Lumpy, 71. 

Marine, 50. 
Marl, 13, 35, 51. 
Marly peat, 50. 
Medium peat, 60. 
Mesquite, 60. 
Moor earth. 60. 
Moss peat, 50. 
Mottled, 51. 
Mountain. 60. 
Mulatto. 51. 

Niggerhead, 61. 

Oak, 51. 

Park, 132. 
Peaty alkali, 51. 
Peaty loam, 60. 
Pine flat, 51. 



Index to Soil Names 



1«S 



Pine barrens. 51. 
Pine woods, 61. 
Plney woods 51. 
Pipe clay, 51. 
Pocoson, 48. 
Post oak flats, 51. 
Post oak prairie, 51. 
Post oak swagrs. 61. 
Prairie, 51. 

Red clay, 47, 51. 
Redlands. 51, 104. 
Redwood, 53. 
Regur, 51. 
Rich black. 73. 
Rough pimply, 50. 

Salt marsh, 51. 
Scrub oak, 51. 
Sedentary. 51, 96. 
Shoepeg, 51. 
Sour, 81. 
Spouty, 52. 
Sterile, 51. 
Stiff, 51. 
Strong-. 51. 
Sugar tree, 47. 

Tallow, 52. 
Tamarack, 52. 
The barrens, 48. 
Tidal., 52. 
Tight, 47, 52. 
Till, 13, 52. 
Transported, 52. 
Tuff. 13, 52. 
Tule land, 53, 110. 

Vegetables, 52. 
Vegetable loam, 52. 
Vegetable muck, 52. 

Wacke, 52. 

Wax, 52. 

Warm, 52. 

Wash, 52. 

White alkali, 53. 

White ash land. 53, 140, 145. 

White clay, 47. 

White gum slash, 50. 

White land, 52. 

White oak, 52. 

Wildgoose land, 53. 

Wornout, 52, 87. 

Yellow prairie, 52. 



SCIENTIFIC NAMES. 

Adobe, 12. 58, 108, 112. 
Alamo clay adobe, 111. 112. 

" clay loam adobe, 122, 123. 
Alkali, 83. 157. 
Alluvial. 94, 100. 
Altamont clay adobe. Ill, 112. 
Alvlso clay, 105, 109, 110. 
Anderson fine sandy loam, 139. 
161. 



Anderson gravelly loam, 135, 161. 
Arbuckle clay loam, 117. 

fine sandy loam, 139, 140. 
" gravelly loam, 135. 

" gravelly sandy loam, 137, 

138. 
loam, 127, 128. 
Arnold clay adobe. 111, 112. 

fine sandy ioam, 139, 140. 
loam. 127, 128. 
" sandy loam, 144. 
Arroyo Seco sandy loam, 136, 162, 
163. 

Bear loam, 127, 128. 
Bellavista sandy loam, 144, 161. 

• Capay clay, 110. 

clay adobe. Ill, 112. 
clay loam. 117. 118. 
Clay, 28, 29, 55, 56, 58, 60, 63, 64, 66, 
68, 70, 71, 72, 76, 80. 82, 84, 89. 
90, 96, 107. 109. 
Clay adobe. 107. 
Clay_loam, 56, 58. 63. 89. 90. 107. 
Clay loam adobe. 107. 
Coarse sand, 55. 56. 58. 66. 71, 89, 107. 
Coarse sandy loam, 107. 
Coastal beech, 106. 
Colluvial, 94, 98. 
Colluvial and alluvial, 54, 100. 
Contra Costa sandy loam, 144. 146. 
Corning gravelly loam. 135. 

loam, 128. 
Corralltos loam, 127, 128. 

Danville clay loam adobe, 122, 123. 
Daulton clay adobe, 111. 112. 
clay loam, 117. 118. 
" sandy loam. 145. 

Diablo clay adobe. 111. 112. 
Dublin clay adobe. Ill, 113. 
clay loam, 117, 118. 
clay loam adobe. 122, 123. 
loam. 127. 129. 
Dunesand. 66, 106. 107. 149, 154, 161. 

163. 
Dunnlgan clay, 52, 109. 110. 

Elder gravelly fine sandy loam. 137. 
silt loam. 125. 
sllty clay loam. 120. 121. 
Enclnal sandy loam. 97. 144, 145. 
Esparto clay, 109, 110. 

clay loam, 117. 118. 
loam. 127. 129. 
Exeter sandy loam. 144, 145. 

Fancher sandy loam, 143. 145. 160, 

161, 163. 
Feather loam, 127. 129. 

silt loam, 53. 125. 
Fine gravel, 55. 
Fine sand. 55. 63, 71. 89. 107. 
140. Fine sandy loam. 56, 58, 66, 71, 89, 
107. 



166 Soils of Califobnia 

Fresno clay loam. 117, 118. Kirkwood .sllty clay abode, 1 H. 

coarse sand, IBO, 151. 
fine sand, 108, 149. 160, 161,, 

163. Lake and marsh, 106, 149, 156. 

" fine sandy loam, 53, 108, 126, Lewie, 117, 119. 

Ill: III' ul- '"'■ '''• ''"'L'^^t- «»• 

gravel, 14^, 161. Llvermore clay, 109, 110. 

gravelly sand, 153, 163. " clay loam, 117, 119. 

" loam, 127, 129, 160. fine sandy loam, 141. 

loamy coarse sand, 151. " gravelly sandy loam. 137, 

red sand, 154, 160, 161. 138. 

sand, 108, 152, 153, 154, 160. loam, 127. 130. 

161, 162, 163. ' silty fine sandy loam. 148. 

sandy loam, 53, 140, 144, 145, I^oam, 63, 81, 89, 91, 107. 
152, 160, 161, 163. Loam adobe, 107, 121. 

Fullerton sandy adobe, 122, 134, lei, 1^°^"^^ coarse sand, 107. 

162, 163. Los Angeles sandy loam, 130. 161. 

Galveston clay, 106, 109, 110, 161, 162. 

Gila clay loam, 117, 118, 163. Madera clay loam, 117, 119. 

" fine sand, 153. " coarse sand, 150, 151. 

fine sandy loam, 139, 140, 161. " fine sandy loam, 139, 141. 

163. " sand, 152, 153. 

loam, 127, 129, 161, 163. " sandy loam, 144. 146. 

silt loam, 125, 161, 163. Marcuse clay loam, 117, 119. 

Gravelly clay loam. 107.^^ ^^^ j^,,,,,p, ^-^/f ",7, '--• 1^6, 139. 

" l^n"?' 7n^ ^"'- " gravelly loam, 109. 135. 

136, 141, 161, 162. 163. 



sand, 107. 



" sandy loam, 107. 
Grldley loam, 127, 129 . 

" sandy loam, 144, 145. 

sllty clay loam. 120. 121 



gravelly sand, 148. 162.163. 
loam. 129. 160. 162. 
sand. 152. 153, 163. 
sandy adobe, 134, 160. 
sandy loam, 144, 146, 161, 



Hanford clay adobe. 111, 113, 162. 

clay loam, 117, 118. 126. 160.,, ' 162. 

161, 162, 163. Marsh. See Lake and Marsh, 

coarse sand, 150, 151. Marysvllle silt loam, 125, 126. 

" Tn^e'slnri^l^l^'?: Ill" .162.Maywood gravelly sandy loan.. 137 

IftQ i.oo. 

fir,o oonH^f i^or,^ 1QQ iAn " fine sandy loam, 139. 141 

nne sandy loam, 139, 140, •• ir>Qm 197 iQn 

" graVel' US' Wl '''' '''' " slfTiolV.: lit; 126. 

loim i?7 i?q ifii Silty Clay loam, 120. 121 

" sS," 152,' ill: III: 161, 162,M«^^°^- 91. 106. 149, 156, 160. 

163. Media clay adobe. Ill, 113. 

sandy loam, 144, 145, 161. " coarse sandy loam, 151. 

silt loam, 125, 126, 140, 162. " fine sandy loam, 139, 141. 
Hardpan. 68, 157. sandy loam, 144. 146. 

Heavy, 90. Medium sand, 55, 56, 58, 71. 

Honicut loam. 127, 129. Mocho fine sandy loam, 139, 141. 

" gravelly fine sandy loam, 137, 
Imperial clay, 109, 110, 161. " loam, 127, 130. 

clay loam, 117, 118, 161. " sandy loam, 146. 

fine sandy loam, 129, 161. Modesto loam. 127. 130. 

'■ grallny loam. 136, 161. TT^'^l «a"«iy l^^"!' l^*. 146. 

loam, 118, 161, 163. Muck. See Peat. 156. 

sand, 152, 153, 161, 163. 
" sandy loam, 140, 144, 145,.. , , , ,,.,,,,-„ 

161, 163. Norman clay adobe. 111, 113. 160. 

silt loam, i25, 161, 163. 
Indio gravelly loam, 135, 136, 161. Oakdale coarse sandy loam, 151. 
fine sandy loam, 139, 140, 149, " sand. 152. 154. 

161. " sandy loam, 144, 146. 

fine sand, 145, 149, 161. Orland fine sand, 152, 160. 

.sand, 153. 161. " fine sandy loam. 139. 141, 160. 



Index to Soil Names 167 

Oxnard clay loam, 117, 119, 130, 161, Sacramento heavy clay, 111. 

162. " loam,' 127, 131, 160. 161. 
" clay loam adobe. 123, 161, 162. " sand, 152, 154. 

163. '• sandy loam. 144, 147. 

" fine sandy loam, 139, 142, 162. " silt loam, 125, 126, 160, 

gravelly loam, 135, 136, 162, 161, 162. 

163 " sllty clay, 116. 160. 

loam, 119, 127, 130, 140, 161, " silty clay loam, 120, 121, 

162, 163. 160. 

sand, 152, 154, 161, 162. 163. Salinas gray adobe, 111, 113, 162, 163. 
" sandy loam, 144, 146, 162. 163, " shale loam, 136, 162. 163. 

" silt loam, 118, 125, 126, 160,Salslpuedes loam ,128, 131. 

162, 163. Sand, 51, 58, 64, 68, 76, 81, 84, 89, 107. 

•D„,.„^ , , J u 100 San Gabriel gravelly loam, 136, 162. 

Pajaro clay loam adobe. 123 .< gravelly sand 148 162. 

fine sandy loam, 139, 142. .. sandy loam, 146, 162. 163. 

light silt loam. Sandhill. See Dunesand. 

loam, 127, 130. c!„„^„ „/i„u^ m-? 

sand 154 Sandy adobe, 10(. 

sandy loam, 144, 146. Sandy clay, 89. 

silt loam, 125, 126. Sandy loam, 56, 70, 71, 89. 107. 

T>«a't ^7^"?^ ^Ina' }Iq IKK 1K« i«iSan Joaquin black adobe, 123. 124. 
^^^^'J^nJq- ^^^' ^^^' ^^^' ^^^- ^^^' 160. 161. 162. 163. 

IDZ, IDO. •• finv nrlf>hf> 111 114 

Placentia clay loam, 90, 117, 119, 180, « ^j|^ loamf 117 119 ' 

11 ™ ^ ., nn ,oo " Clay loam adobe, 123, 

clay loam adobe, 90, 123, 124 162. 

124, 160. „„,.., " fine sandy loam. 139, 

coarse sandy loam, 90, 147, I43 ig2. 

« 1^2- " gravelly loam, 135, 136, 

fine sandy loam, 90, 139, IgO 

iJl^'qn^ii^<f^97^^iq^rf^ifi? " gravelly sandy loam, 

loam, 90, 119, 127, laO, 163. J37 j3g 

^o^"], t^o^e^ 52 90 121. .. loam,' 128,"l31, 160,163. 

^ • ^i'u ^•^•oA ,'o. ,<,« " red adobe, 124, 134, 160, 
sandy adobe, 90, 134, 160, 162. 

l^- , „„ .on 1^0 " sand,'l52, 154, 160, 161. 

r.i^„o„ i.^ 144, 147,160, 161 162,163. - ^andy loam. 144. 147, 

Pleasanton clay adobe. 111, 113. 160 162 163 

;; gravelly clay loam, 120 ganta Clara sand, 152. ' 

gravelly sandy loam, 137,santa Cruz loam. 128. 131. 

• " sand 154 

l^^^' \^'''J^^^'aa i^.7 " sandy loam, 52, 144, 147. 

fi^^ L J^ 1^1 '^^ ^^^- Santa Rita clay adobe. 111, 114. 

fine sandy loam. « innm 19S 1^1 

Poplar fine sandy loam, 139. 142. .. siltv clav loam 1^0 121 

124. Santiago silt loam, 118, 125, 161, 162, 

" coarse sandy loam, 151. ,, ^ 1^3. ,„„ ,^„ 

" loam 127 131 fin® sandy loam, 139, 143, 

163. 

Redding gravelly loam, 135, 136. lei.gheridan sTndv loa^i^'99''^l'4ri47 162 
gravelly sandy loam, i38.»ne"aan sanay 10am »» i44, 14/. ibz. 

" loam 127 131 161 Sierra adobe, 124, 134, 160, 161. 

Residual, 54, 94, 96.' ' ' " clay loam, 117, 119, 162. 

Riverwash, 106, 155, 160, 161,162,163. " loam, 122, 128, 131. 

Rock outcrop, 155. loam adobe. 121, 122, 131, 162. 

Rough stony land, 106, 155, 161, 163. " sandy adobe, 134, 161. 

" sandy loam, 144, 147, 162. 

Sacramento clay, 53, 109, 110. <,„/' ,, ^V'^J^'^T' ^^^' ^^^• 

clay adobe. 111, 113. f ! *' ^\' ^^'^^^ V;. 

clay loam, 117, 119, 163. Silty clay. 107, 106. 

fine sand, 149, 152. Silty clay adobe, 107. 
""^60^161 ^°''™' ^^^' ^*^' Silty clay loam, 90, 107. 

gravelly sandy loam, Silty fine sandy loam, 107. 

137, 138, 160, 161. Silt loam, 56, 58, 66, 71, 89, 107. 



168 



Sou^ OF California 



Sites clay adobe, 111. 114. 

" clay loam adobe. 123, 124. 160. 
gravelly sandy loam, 137, 138. 
•' loam, 128, 131. 160. 
" sandy loam, 144, 148, 160. 
silt loam. 125. 127. 
Soledad gravelly sand. 148. 162. 163 
Stockton clay adobe. 111. 114. 163. 
clay loam. 117. 120. 
"^ clay loam adobe, 52, 123 

124, 161. 162. 163. 
" fine sandy loam. 139, 143 

160. 163. 
loam 128, 132, 163. 
loam adobe, 121, 122. 163. 
silt loam. 125. 127, 163. 
Stony clay loam. 107, 
Stony loam, 107. 
Stony sandy loam, 107. 
Sunol loam, 128. 132. 
Sutter clay. 109, 111. 

clay loam adobe, 123, 124. 
loam, 128, 132. 
sandy loam, 144, 148. 

Tehama clay. 109. 111. 

" gravelly loam, 136. 
silt loam, 127. 
Tassajero clay loam, 117, 120. 
Tuscan stony loam, 122. 

" stony sandy loam, 137. 



Ulmar fine sandy loam, 139, 143. 
loam. 128. 132. 

Vallecltos clay adobe. 111. 114. 
loam, 128, 132. 
" stony clay loam, 122. 

Very fine sand, 55, 89. 
Vina clay adobe. 111. 114. 
clay loam. 117. 120. 
fine sandy loam, 137, 139. 143. 
loam. 128. 132. 
" gravelly fine sandy loam, 137. 
silt loam, 127. 

Watsonvllle clay loam adobe, 123, 124. 
loam, 128, 132. 
" sandy loam. 144, 148. 

Willows clay. 109, 111. 160. 

clay adobe, 111, 114, 160. 
clay loam, 117, 120, 160. 
loam, 128, 132, 160. 
silty clay loam. 120, 121, 160. 

Yolo clay, 109, 111. 

" clay loam, 117, 120. 

fine sandy loam, 139, 143. 
" loam, 128, 133. 
" silt loam, 125. 127. 
" sllty clay, 116. 



GENERAL INDEX 



Absorption, 60. 
Abused soils. 17. 
Acid rocks. 11. 
Adaptability to crops, 92. 
Adobes, the, 108. 
Adsorption, 60. 
Aggradation, 31. 
Agricultural geology, 7. 
Air retained. 30. 
Alkali, black. 53, 157. 
Alkali, limit.s of endurance, 158. 
Alkali soils. !)2. 1^7 
Alkali, wliite, 53, 157. 
Aluminum. 15, 17. 
Alluvial cone, 33. 
Alluvial, plain, 21. 33. 
Ammonia, 76, 78. 
Amphibole, 14. 
Animal life in tlie soil. 82. 
Ants. 83, 85. 
Atmosphere. 9, 25. 
Apatite. 15. 
Aqueous rocks, 11. 
Argillaceous material. 11. 
Arid regions, 34, 35, 74, 76, 84, 90. 

Bacterial. 18. 74, 76, 77, 81, 82. 85. 
aerobic, 78. 
anaerobic, 78. 
" bacillus, 78. 



Bacterial, bacillus mycoldes, 78. 

baggiatoa, 78. 

effect of moisture. 80. 

favorable conditions. 80. 

effect of temperature, 80. 
" micrococcus, 78. 

number of, 28, 80. 

splrllli, 78. 
" unfavorable conditions. 80. 

vibrio. 78. 
Base, level, 22, 34. 
Base leveled plain, 23. 
Basic rocks, 11. 
Basin, 22. 
Bedrock, 11. 
Beetles. 83, 85. 
Bergmeal, 35. 
Blotite. 14. 
Boulder clay, 35, 73. 
Broken block lands, 23. 

Calcareous material, 11. 

Calclte. 14. 

Calcium, 15. 

California, area, 37. 

Canyon, 32. 

Capillary water, 62. 63. 

Carbonation. 26. 

Carbonic dioxide, 19, 28, 69. 78. 

Cascade Province, 42. 46. 



Qenebal IND£X 



169 



Case harden, 68. 

Changres In names, 109. 

Channel, 32. 

Checkingr. 68. 

Chemical analysis. 74. 

Chemical work of atmosphere, 26. 

Chlorite, 15. 

Chlorine. 15, 17, 60. 

Classification, 47. 158. 

Coarse sands, the, 139, 150, 151. 

Coarse sandy loams, the, 139. 151. 

Coastal plains, 20, 24. 

Coast Provinces, 38, 45. 

Coast Range^ northern, 39. 

Coast Range, southern, 39. 

Cohesion, 69. 

Colloidal rocks, 12. 

Colusa Area. 102. 

Conglomerate, 12. 

Correlation, 108. 

Critical moisture, 65. 

Crumb structure, 68. 

Crystalline rocks, 11. 

Degradation, 31. 
Degraded plains. 21. 
Delta, 21, 33. 
Deposition, 33. 
Desert, 40. 
Dikes, 33. 
Distributaries. 33. 
Dolomites. 12. 
Drainage. 30, 62. 70. 
Drift, 12. 
Drift plains, 21. 
Drumlins. 36. 
Dunes, 26. 

Dunesands, the, 149. 
Dust. 26. 

Earth, the. 8. 
Earth worms. 82, 85. 
Electricity. 71. 
Elements, 15. 

" atmospheric. 17. 

Enzymes. 81. 
Eollan plains, 21, 24. 
Eolian rocks, 12. 
Eollan soils, 47. 
Eskers, 35. 
Evaporation. 66. 

Factors, 10. 
Pan. 33. 
Feldspar, 14. 
Ferns. 81. 
Ferruginous. 11. 
Fertilizers, mineral, 59, 74. 
" organic, 59, 74. 

Film water. 62. 64, 68. 
Fine sandy loams, the, 134. 
Flocculation, 16. 
Flood plain, 21. 32. 
Fragmental rocks, 12. 
Fungi, higher, 81. 

Geologic provinces. 43. 
Geomorphogeny, 25. 
Geomorphology, 205. 



Glacial drift, 35. 

plains, 21. 
Glaciers, 8, 35. 
Gneiss, 12. 
Gradation. 31. 
Granite, 11. 12, 
Granular structure. 65, 68. 
Gravel, 139. 

Gravelly fine sandy loams, the, 137. 
Gravelly loams, the, 134, 135. 
Gravelly sands, the. 139, 148. 
Gravelly sandy loams, the, 134. 
Gravity, 69. 

Great Basin, 23, 40, 45, 46. 
Great Valley, 22, 39, 44, 96. 105. 
Greenstone. 12. 
Ground water level. 66. 
Ground water surface, 66. 
Gravitational water, 62. 
Gyppum. 14, 64. 

Hardpan, 68. 157. 
Hematite, 15. 
Highlands. 22. 
Hills, 22, 

Hills of accumulation, 22. 
Hills of erosion, 22. 
Humus, 66, 82, 83. 84. 
Hydration, 26. 
Hydrosphere, 9. 
Hygroscopic water, 63. 

Ice, 30. 

Igneous rocks, 12. 
Imperial area, 102. 
Indurated, 11. 
Interment valleys, 22. 
Intrusive rocks, 12. 
Iron. 15. 17. 72, 73. 
Isolated mountain. 22. 

Karnes, 35. 
Kaolin. 14. 
Klamath province, 42, 46. 

Lacustrine plain. 21. 
Lake, plain, 20. 21. 
Lakes, 34. 
Lakes, glacial, 35. 

" intermittent, 35. 

" volcanic, 35. 
Land forms, 20. 
Lassen Peak, 23. 
Lava, 12. 
Lichens, 81. 
Life in soil. 78. 
Lime, 14. 16. 60. 78, 81, 83. 
Limestone, 12, 83. 
Lithosphere. 9. 

Livermore area, 97, 99. 103. 105. 
Lepidollte, 14. 
Levee, 34. 

Loam adobes, the, 120. 
Loamy coarse sand, 139. 
Loess, 13, 50. 

Magnesia, 17. 
Magnesium. 15, 59. 
Mantle rock, 11. 13. 
Marble. 13. 



170 



Soils of California 



Marginal moraines, 8S. 
Marl, 13, 35. 
Mature valley, 34. 
Maximum moisture, 66. 

Minerals, 11. 13, 88. 

Modesto-Turlock area, 102. 

Molds. 82. 

Mosses, 81. 

Mountain, 22. 24. 

Mt. Lyell, 41. 

Mt. Shasta, 23, 27. 

Mt. Wliitney, 38. 41. 

Muscovite, 14. 

Names, changed, 160, 161. 162, 163. 

Names, common, 51. 

Nitric acid, 78. 

Nitrogen, 15, 18, 60, 69, 76. 78. 82. 

Nitrogen from air, 80. 

Ooze, 13. 

Optimum moisture, 63, 65, 66. 

matter, 72. 76, 77. 
Outcrop, 11. 
Outer valley, 32. 
Oxidation, 26. 

Pajaro area, 110. 

Paragonite, 14. 

Peat. 149. 

Peneplain, 23, 31. 

Phosphorous, 15, 16, 60. 74. 78, 81. 

Piedmont alluvial plain, 33, 

Plains, 20. 

of degradation, 20. 
Plasticity, 68. 
Plateaus, 21, 24. 
Poisoned soils, 17. 
Potash, 16, 58, 60, 78, 81. 
Potassium, 15, 59, 60. 
Pyroxene. 15. 

Quartz, 13. 
Quartzite, 13. 

Recent stream deposits, 33. 

Red Bluff area, 98. 103. 

Regolith, 13. 

Riverwash, 149. 

Rocks, 11. 

Rough, stony lands, the, 149. 

Run off, 28. 

Saccharomycetes, 78. 
Sacramento area, 99, 100. 
Sandstone. 13. 
Sandunes. 26. 
Santa Ana area, 104. 
Seasons, 8. 

Sedimentary rocks, 11. 
Sediment, 32. 
Seepage, 31. 

Series, 88, 90. 
Alamo, 95, 105. 
Altamont, 94. 97. 
Alviso, 95. 
Anderson, 95, 103. 
Arbuckle, 95, 103. 



Arnold, 94, 96. 
Capay, 95, 104. 
Contra Costa, 94, 97. 
Corning. 95, 104. 
Diablo, 94, 98. 
Danville, 95, 99. 
Daulton, 94, 96. 
Dublin, 95, 100. 
Elder, 95, 103. 
Encinaz, 94, 97. 
Esparto. 95, 102. 
Feather, 95, 105. 
Fresno, 95, 103. 
Galveston, 95. 
Gila, 95. 101. 102. 
Grldley, 95, 104. 
Hanford, 40. 95, 103. 
Imperial, 88, 95, 102. 
Indio. 95. 100. 
Klrkwood. 95, 104. 
Livermore, 95, 100. 
Madera, 96. 
Maricopa, 95. 99. 
Maywood, 95, 103. 
Media, 94, 97. 
Mocho, 103. 
Oakdale. 95, 102. 
Orland, 95, 102. 
Oxnard, 95, 99. 
Pajaro. 95, 102. 
Placentia, 90, 95, 99. 
Pleasanton, 94, 97. 
Portersville, 94, 96. 
Redding, 95, 104. 
Sacramento, 88, 95, 105. 
Salsipuedes. 95, 99. 
Sand, 139. 

San Joaquin, 88, 96, 106. 
Santa Cruz, 94, 98. 
Santiago, 95, 104. 
Santa Rita, 96, 105. 
Sheridan, 95. 99. 
Sierra, 94, 97. 
Sites, 95, 100. 
Stockton, 96. 105. 
Sunol, 95, 100. 
Sutter, 95, 99. 
Tehama, 94. 98. 
Tuscan, 94, 98. 
Ulmar ,95, 100. 
Vallecitos, 94, 98. 
Watsonville, 94, 98. 
Yolo, 95, 102. 

Shale. 13. 

Sierra Madre Range. 33. 

Sierra Nevada province, 37, 43. 

Sierra Nevada Range, 23, 33, 43, 47. 

Silicon. 15. 60. 

Silty fine .«!andy loams, the. 139. 148. 



GENsaAL Index 



171 



Slate, 13. 
Sodium. 15, 59. 
Soils, adaptation of, 75, 92. 
atmosphere, 68, 69. 
classes, 88, 105. 
color of, 72, 76. 
creep, 28. 
dark, 70, 73. 
deep, 70. 
" deterioration. 86. 
fertility, 74, 87. 
fine, 71. 
" forming materials, 70. 
" forming processes, 10. 
heavy, 72. 
light, 72, 73. 
" minerals, 11. 
" moisture, 62, 70, 80, 91. 
" movement, 85. 

names, 47, 89, 108. 109. 
odors, 74. 

particles, 54, 55, 56, 60. 88. 
" permanence. 86. 
" processes, 10. 
" provinces, 58. 

self purifying, 78. 
series, 54. 
" solution, 59. 
" temperature, 69, 80. 
" temperature ,69. 80. 
texture, 57, 62, 70, 72. 
types, 7, 88. 
Special soils, 106. 
Stony clay loams, the, 122. 
Stony loams, the, 122. 
Stony sandy loams, the, 134, 137. 
Strata, 11. 

Stream, overloaded, 32. 
Streams, 31. 
Structural plains, 20. 
Structural valleys, 22. 



SubBOil, 84. 

" calcareous, 85. 
Sulphur, 15. 17. 

Temperature, 26. 

Terminal moraine, 35. 

Till, 13. 

Tilth, 65. 

Topographic provinces, Zl. 

Toxic bodies. 77. 

Tufa. 13. 

Tuff, 13. 

Valley forms, 34. 
Valleys, 22. 
Valley trains, 36. 
Virgin soil. 25. 
Vitreous rocks, 11. 
Volcanic lands, 23. 

Water, 28. 

absorbed, 61. 

capillary, 62. 

film, 62, 64. 

gravity, 62. 

hygroscopic, 62, 63. 

hydration, 62, 64. 

work of. 28, 86. 
" solvent action of, 29. 
" storage, 29. 

table, 66. 

undergound, 30. 
" vapor, 63. 
Weathering, 27. 
Wind erosion, 26, 86. 
Wind worn rocks, 21. 
Woodland, area, 100, 102. 110. 
Worn down plains, 21. 

Young valley, 34. 



OCT 29 1313 



